At the source of networks: identifying ties between individuals from a population register

The population register for Lubartów lists six inhabitants residing in 1938 at 11 Rynek II, the town’s market square. Kielman and Etla Bajgielman, and their daughter Chana born in 1907, were already living there when the register was established in 1932. Moszek-Hersz Kawa moved there in August 1937, and his son Chaim-Alter was born eleven months later. In the meantime, Wincenty Jezior, a 31-year-old baker, also arrived. He was the only person of the Roman Catholic faith in a dwelling where all other residents are identified as Jews. What is more, he was the only Catholic on a street where 235 of the other 240 inhabitants were Jewish (the religion of the remaining seven is not recorded). What ties did Wincenty Jezior have with the inhabitants of his home and his street? Do these ties help us understand this exceptional case, in an urban space highly segregated by religion? Beyond this case, how can we reconstitute the ties between a town’s inhabitants from a historical source, a population register designed to control the movements of its inhabitants?[1]We possess the register entry, in the form of a database, as well as the original digitized source.

Identifying the ties between inhabitants of a social space paves the way for in-depth knowledge of the town’s social morphology. It is also central to linking the residential, migratory, and social trajectories of residents, as well as the social relationships in which they found themselves. A register such as that of Lubartów is a particularly rich source in this respect: many ties between the inhabitants were recorded, going well beyond kinship (such as economic or residential ties).

However, identifying them poses a number of methodological difficulties. In the Lubartów register, each double page corresponds to a dwelling; the residents were registered as they arrived, and the ties between them were recorded in relation to the “head of household.” A first difficulty is therefore the scale of analysis: a source whose unit of registration is the dwelling does not encompass (or provides only rare clues about) ties between individuals who did not live together. Moreover, the categories in the source are only partially standardized: the same kind of relationship was recorded in different ways. Finally, although it is possible to glean additional information about the ties from other columns in the source, it is often partial or uncertain. What techniques can be applied to this population register to identify ties between individuals, both inside and outside of dwellings.


A diversity of ties inside dwellings

Dwellings are good starting points, especially because of the diverse ties between individuals that can be identified within them, whether they are explicitly indicated, or can be identified or assumed through various clues. Let us consider the example of 11 Rynek II (see the photograph below).

The residents of 11 Rynek II in Lubartów. Lublin State Archives (APwL), 35/43/0/7/46/50-51, Lubartów population register, vol.46 © Archiwum Państwowe w Lublinie

First, we can see filiation and conjugal ties. The residential status column (column 5) provides initial information regarding these ties: Chana Bajgielman was Kielman Bajgielman’s “daughter” (corka), while Etla née Zandmer was Kielman’s “wife” (zona). This matrimonial connection also appears in the marital status column (column 8): they were married (malz.) in 1895. The information in the occupation column (column 6) also points in this direction, since Etla is said to be “with the husband” (przy mezu), and Chana “with the parents” (przy rodzicach). The first and last names of the residents (column 2) and their parents (column 3) also confirm that Chana is Kielman’s and Etla’s daughter.

Other relationships are given with less precision: Moszek-Hersz Kawa was a “member of the family” (czl. rodziny) of Kielman Bajgielman. It can be assumed that Moszek-Hersz was Chana’s partner, as they are listed as the father and mother of a child born in 1938, Chaim-Alter Kawa, whose parents’ first and last names and residential status appear in the register (“son of Nr 4” – syn p. Nr 4 -, i.e. of Moszek-Hersz).

Such ties were not limited to kinship, as ownership and tenancy relationships also appear: Kielman is listed as the “owner of the dwelling” (wlasciciel domu), and Wincenty Jezior as a “worker” (pracownik). The latter status also indicates a professional relationship: Wincenty’s profession (“baker”, piekarz), combined with his status as a worker, probably indicates that he worked for Kielman, whose profession was “bakery owner” (wlasciciel piekarni).

The configuration of ties at 11 Rynek II suggests that these six residents also had an additional co-residence tie. However, being registered on the same double page of the register does not always mean they lived simultaneously at the address, since successive residents were registered as they arrived. So how can we determine who lived together?

Identifying co-residence ties within dwellings

Co-residence is a good indicator of “shared daily life,”[2]In French, “le partage du quotidien”: Florence Weber, Penser la parenté aujourd’hui. … Continue reading with all of the exchange and interaction that this can imply. A source whose basic unit is the dwelling can be used to identify co-residence, namely by analyzing the various dates registered. For example, when a person’s date of arrival (moving to the address or arriving in town) was later than the date of departure (death, moving, leaving town, and/or removal from the register) for a resident previously registered on the same double page, it can be assumed that they did not co-reside.

Let us consider the example of apartment no.1 at 8 Niecala Street (see table below). Mordko, Brucha, and Pesa-Cywja Bajgielman left Lubartów on October 6, 1932. They were replaced three weeks later by Jozej-Szczepan Kondracki, his wife Marja, and their 17-month-old daughter, Janina-Teresa. After their departure in December 1933, the apartment remained empty, according to the register, for almost four years, until the arrival of the Bogdanski family. Stefania and her children Jerzy and Krystyna lived there for only one month, and Zdzislaw-Leon also left the house two weeks later, in mid-January 1938. Stanislawa-Tekla and her son Ryszard-Oskar had already arrived in Lubartów when the Bogdanski family moved in, and did not leave the town until September 1938; since the register does not provide information on any of the dates when the residents of this apartment moved in or out, there is no indication that the Bogdanski and Bikner families did not live there together.

However, there are limitations to identifying co-residence from the dates recorded in the register. Firstly, movements and their dates were not systematically filled in. A date of departure or death that was not recorded does not mean that the residents did not leave or die, especially in the case of the Jewish population during the flight and deportation movements of the Second World War. For example, it is likely that in some of the 118 addresses in Lubartów where there are several “owners of the dwelling” or “main tenants” whose dates do not indicate that they did not co-reside, the departures or deaths of successive residents were in fact not recorded. Moreover, even the dates of departure and arrival recorded by the administration may differ from the actual dates of these movements. Nevertheless, if we stick to this method of identification, we can distinguish, within the 1,928 residences in Lubartów, 2,225 subsets of inhabitants who had a co-residential relationship with each other.

However, the ties shown in the register go far beyond just the co-residents. The challenge is to identify, as widely as possible, what linked the town’s inhabitants. So how can we systematize identification of the wide range of ties made possible by the register both inside and outside dwellings?

Identifying ties inside dwellings: from the statuses recorded in the source


Two types of information enable an initial identification of ties within dwellings: residential status (left blank for only 13 individuals out of the 11,950 registered) and marital status (provided for 4,341 individuals). The challenge is to propose a coding similar to the source’s categories, which is to say how individuals—the residents and local administration—qualified and categorized these ties.[3]The Lubartów register was completed from forms filled in directly by the residents of a dwelling, … Continue reading

We use identifiers to link individuals together; each individual in the database has a unique identifier. We then create a set of lines for each individual, with each line representing one of the individual’s ties. The newly created database thus contains three columns: the first corresponding to the individual’s identifier, the second indicating the type of tie (such as “daughter of” or “brother of”), and the third containing the identifier of the tie’s recipient.

Identifying ties from residential status

The residential status entered in the register is a first type of information that makes it possible to identify ties within dwellings. This status was recorded on each double-page spread in relation to a reference person, most often the first person listed, except when the reference person was specified (e.g., “son of no. 2,” syn p. nr. 2), or when new residents replaced previous ones in the dwelling. With information about residential status, linking individuals by their identifiers is in some cases relatively straightforward: for example, if a person is described as a “daughter” (corka) or “sister” (siostra), the identifier of the reference person in the dwelling will be associated. From these first ties, it is possible to identify new ones: for example, “daughters” and “sons” (syn) whose father and mother identifiers are identical can be considered siblings; each of these siblings will then be associated with the identifiers of their brothers and sisters.

However, not all residential statuses explicitly refer to ties. This is especially true for those that indicate ownership or rental status: “owner of the dwelling” (wlasciciel domu), “primary tenant” (glowny lokator), and “subtenant” (sublokator). It is possible to identify some ties from these statuses, for example those of tenancy between the owner of a dwelling and tenants or subtenants residing in the same dwelling; the tenants and subtenants will then be associated with the owner’s identifier. However, there are many rental relationships that cannot be identified in this way from the register, especially when there were tenants and/or subtenants residing in the dwelling but no owner; this was the case in 711 of the 1,739 dwellings in Lubartów at the end of 1932.

Similarly, the professional ties that can be identified from residential status alone remain limited. Apart from the one case where the residential status indicates a relatively precise professional tie, that of “servant” (sluzaca), there remain 235 individuals whose status was simply recorded as “worker” (pracownik, pracownica); given the polysemy of the term, we do not know the exact professional tie they had with the other inhabitants of their dwelling. For example, how many were servants? Cross-referencing this residential status with the occupation recorded in the register provides the first elements of an answer. Out of the 235 “workers” in Lubartów, the occupation for 40 of them is “servant” (sluzacy, sluzaca); we can thus assume they were servants of the owner or the primary tenant of the dwelling in which they resided, and associate them with the identifier of this owner or tenant. Similarly, at 11 Rynek II, it was by crossing Wincenty’s residential status as “worker” with his occupation as “baker” that we deduced he was the employee of the dwelling’s owner, who also owned a bakery.

Identifying ties from marital status

Marital status is a second kind of information that can be used to identify ties within dwellings. While information on residential status already mentions “wives” (zona) and “husbands” (maz), marital status directly identifies conjugal ties: the Lubartów register indicates the order number of the person on the double page to whom this person is married. All that is required next is to associate their identifiers: 3,690 of the town’s inhabitants can be linked to their spouses in this way.

Information on conjugal ties is not limited to marriage. Marital status also indicates the presence of some unmarried couples (nieslubna zona, niesl. maz), a divorced person (rozwiedziona), and widowed individuals (wdowa, wdowiec). However, the spouse’s order number is rarely given in the case of unmarried conjugal relationships. This is the case for only 2 of the 157 persons listed as “unmarried” in the marital status column. Moreover, in the case of divorced or widowed persons, since these individuals no longer had an administrative relationship, the marital status alone does not allow for associating them with their former spouse.

Nevertheless, we already have, with this first identification based on residential and marital statuses, several types of ties within dwellings. Its application to 11 Rynek II provides an overview (see the table below).[4]Columns for “name” and “name of the tie recipient” have been added here to … Continue reading

However, identifying ties within dwellings in this way does not enable us to link individuals together if they did not reside together. For instance, while Wincenty Jezior had an economic and residential tie with the Bajgielmans, with whom did he have matrimonial, filiation, or sibling ties? Were the Bajgielmans of Niecala Street and 11 Rynek II related? In short, how can we identify the ties without restricting ourselves to the limits of the dwelling?

Identifying ties outside the dwelling: using first and last names

Another way of determining ties using identifiers is to venture outside dwellings and associate individuals on the basis of their first and last names. The latter are frequently used to reconstruct kinship networks, from both historical[5]Karine Karila-Cohen, “Le graphe, la trace et les fragments. L’apport des méthodes … Continue reading and contemporary[6]Catherine Capron, “Essai de reconstruction automatique des parentés à partir du registre de … Continue reading sources.

Since the Lubartów register in most cases shows the last name, maiden name (if any), and first name of the mother, as well as the last name and first name of the father, it is possible to at least search for the father, mother, and siblings of each person listed in the register. To find an individual’s father with this technique, we search the entire database for a resident with the same last name (or whose last name corresponds to the maiden name in the case of married women), and whose first name corresponds to the father’s first name. To locate an individual’s mother, we look for a resident with the same last name in the case of married mothers (or whose name matches the maiden name for married daughters), whose maiden name matches the mother’s maiden name (or the mother’s last name if the mother is not married), and whose first name matches the mother’s first name. Finally, associating the identifiers of individuals with the same last name (or maiden name in the case of married women), along with the same first and last names of the father and mother, allows for identifying siblings. Combining individuals who share only their father’s or mother’s first and last names also makes it possible to identify half-siblings.

By associating the names of the inhabitants without being restricted to the boundaries of dwellings, these dwellings can be linked together. To take our two previous examples, since Mordko Bajgielman of Niecala Street had—like Chana Bajgielman—a father whose first name was Kielman, and a mother whose first name was Etla and whose maiden name was Zandmer (which corresponds to the maiden name of Etla Bajgielman of 11 Rynek II), identification of ties via names allows for coding Kielman and Etla respectively as the father and mother of Mordko, and Mordko and Chana as brothers and sisters. The eldest son, born in 1903, therefore probably left the parental home before the register was opened, while his sister, who was 4 years younger, remained there until she moved out on her own in 1937. Other relationships arise from these parent/child and brother/sister relationships: for example, the children of two siblings identified by name may be considered cousins. For instance, Chaim-Alter Kawa of 11 Rynek II will be associated with the identifier of his cousin Pesa-Cywia Bajgielman of Niecala Street, and Pesa-Cywia with that of Chaim-Alter.

The identification of ties via names also allows us to complete the ties previously identified within dwellings. For example, while the residential status column for 11 Rynek II only indicates that Moszek-Hersz Kawa was a “family member” of Kielman Bajgielman, the search for ties based on names reveals that the identifier of Chaim-Alter Kawa’s mother is that of Chana Bajgielman. Therefore, we can assume that Moszek-Hersz was probably Chana’s (unmarried) companion, and that Kielman was Chaim-Alter’s grandfather. In sum, this technique of identifying via names clearly fleshes out the ties found between the inhabitants (see the table below).

However, this technique of identifying ties through names has its limitations. The first is homonyms. For example, there are 7 Czeslaw Jeziors in the Lubartów register, and 1,991 individuals have the same first and last name as at least one other individual in the register. The identifiers found are therefore frequently multiple for the same person, which does not allow us to isolate an identifier, and therefore a tie recipient. The identifier found can also be that of an unrelated homonym. Moreover, the spellings of the same name vary within the register, with two equivalent names potentially appearing to be different. In the case of the Lubartów register, the use of the soundex algorithm developed as part of the Lubartworld project partially solves this difficulty: it can code ties by taking these spelling variations into account, namely by identifying ties from their soundex rather than from names. This makes it possible to identify more relatives, even if the multiple identifiers are also more numerous (see table below). A final limitation of identifying ties by name is that it mainly accounts for modal kinship configurations; for instance, it does not account for “non-legitimate” children or siblings, who do not bear the same last name.


Once all these ties have been found both inside and outside dwellings, there are still cases where we can identify the existence of a tie, but where its recipient remains unknown or uncertain. What to do in such cases?

Identifying ties when information is missing or uncertain

The failure to isolate an identifier for a given tie may either be because the recipient of that tie did not reside in the dwelling and/or in Lubartów, or because the various tracing techniques were unable to identify the tie. In the latter case, knowing the existence of the tie may still be useful, as it suggests that a recipient of the tie (e.g., a son or daughter if a father was identified) was probably residing in the town when the individual in question (in this case, the father) was entered into the register.

Identifying recipients of supposed ties’

In a number of cases, various clues can identify at least one supposed recipient of the tie; it is then possible, for instance, to associate the identifier of a “supposed spouse” or “supposed mother” with an individual. This is how direct ties (spouse, parent/child, brother/sister) can be identified from the numerous indirect ties appearing in the register, especially in the residential status column. For example, this can be used to identify the father of a “son of the husband” (pasierb) or the husband of a “wife of the brother” (synowa). For instance, in apartment no.1 at 9 Browarna Street (see photograph below), Piotr-Ryszard Krasuski is listed as the “daughter’s husband” (ziec); he is probably the husband of Eleonora Krasuska née Koziarska, the only “daughter” (corka) of the owner residing in the apartment. This tie is “assumed” because even when a “daughter” is in the same dwelling as a “daughter’s husband,” the latter could also be the husband of another daughter of the reference person of the dwelling, who is not residing in this dwelling or even in Lubartów.

The residents of apartment no.1 at 9 Browarna Street. Lublin State Archives (APwL), 35/43/0/7/39/34-35, Lubartów population register, vol.39 © Archiwum Państwowe w Lublinie

Leaving some ties without a recipient

There are still cases where we do not have enough clues to identify or to assume the recipient of the ties; the ties subsequently remain without recipient, at least initially.

In fact, even the ties already entered in the register, especially in the residential status column, do not always allow us to isolate the supposed recipients of these ties. This is especially true when we seek to identify direct ties from the indirect ties indicated, but this time we find no possible recipient within the dwelling, or on the contrary we find several. For example, a “brother’s son” (brataniec) cannot be associated with his father if no “brother” (brat) is found in the dwelling; nevertheless, it is still possible to code this “brother’s son” as the supposed child of someone present in the town at the time of the child’s entry in the register. In other cases, there are several possible recipients of the tie in the dwelling, such as several “sons” (syn) where there is a “son’s wife” (synowa) whom we are trying to link to her husband. For example, at 9 Browarna Street, the “son’s wife” Anna Koziarska (line 6) could be the wife of either Stanislaw (line 3) or Jozef (line 5) Koziarski, both “sons” of the owner. We can initially code her as the supposed wife of someone living in Lubartów, without associating a husband with her. The other techniques for identifying ties then make it possible, in a number of cases, to complete these ties without a recipient. Here again, it is Anna Koziarska’s marital status (“married to No. 5”, malz. patrz Nr. 5) that ties her to her husband Jozef.

Similarly, while it is often insufficient on its own to associate individuals with each other, the “profession” entered in the register nevertheless can identify numerous ties. Some “occupations” thus refer directly to family ties, especially when inhabitants are designated as “with” (przy) or “dependent on” (na utrzymaniu) someone. For example, a person listed as “with husband” (przy mezu) will be coded as married (to a person living in the town at the time the information was entered in the register). Similarly, a resident whose “occupation” is “with son-in-law” (przy zieciu) will be coded as both a step-parent (in the sense of a relative of the son’s or daughter’s husband) and a parent.

Completing ties with more specific clues from the source

When the previous techniques for identifying ties cannot complete these supposed ties or ties without recipient, there is sometimes more specific information in the register that can provide clues for specifying these ties.

For instance, in the Lubartów register the names (of spouses in particular) occasionally appear in the various columns, constituting as many possible recipients for the identified ties. With regard to matrimonial ties, the spouse’s name appears in the marital status column for 181 of the 3,898 “married” persons, and in the residential status column for 2 of the 156 “unmarried women” and the only “unmarried man.” In addition, there is a single husband’s name in the “occupation” column (Ruchla Wajc is said to be “with the unmarried man Biegancu”, przy niesl. mezu Biegancu).[7]Lublin State Archives (APwL), 35/43/0/7/47/144-145, Lubartów population register, vol.47, pages … Continue reading When these names are extracted from the database and cross-referenced with other people with this name (or the corresponding soundex), the identifiers of the two relatives can be associated. For example, for the 181 “married women” for whom a name appears in the residential status column, 26 potential spouses can be found by searching the database for the soundex of the mentioned names, and 11 are found by searching the names themselves. In this case, this tracing technique allows us to link spouses across dwellings,[8]In fact, it is especially in cases where the spouse is not in the same dwelling that a name is … Continue reading and in a few cases to extend the identification of conjugal ties beyond marriage alone.

This technique can also capture types of relationships that are relatively uncommon in the town. For instance, Adela and Helena Dolak,[9]Lublin State Archives (APwL), 35/43/0/7/43/124-125, Lubartów population register, vol.43, pages … Continue reading who were aged 10 and 8 when they arrived in Lubartów in 1934, and whose residential status indicates they were “wards” (sierota na wychowaniu)—the only ones in the register—are said to be “dependent on Jaskowiaka” (na utrzymaniu Jaskowiaka) by virtue of their “profession.” While no individual in the register has this name, a single inhabitant has a name whose soundex coincides with that of “Jaskowiaka”: Michal Jaskowiak, an “unskilled worker – day laborer” (robotnik niewykwalifik. wyrobnik) registered as a “subtenant” (residential status) in the same dwelling on Lubelska Street.[10]The form “Jaskowiaka” comes from the declension of the name “Jaskowiak”. A recipient was thus found for this unique tie of “dependence.”


In sum, a historical source such as a population register allows for identifying a wide range of ties between inhabitants (co-residence, kinship, ownership/rental, professional ties). These ties can be identified both inside (via the statuses entered in the source) and outside dwellings (especially through the names), whether or not we manage at first to pair the individuals caught in these ties. To identify ties beyond the closed space of Lubartów—to which a local source such as the register gives access—it would have to be cross-referenced with the many complementary sources that can provide information on individuals and their ties.  

Nevertheless, identifying ties within the town already opens up many avenues for research. It makes it possible to describe the configuration of ties at the dwelling or individual level with regard to the social properties that characterize them, religious ones in particular. It also paves the way for networks analyses at the group, street, or town level, thereby incorporating the logic of local belonging, and its role in social and migratory trajectories.[11]On the implementation of this approach in the case of the Jews of Lens (France), see for example … Continue reading