Two men named Jan with the same surname lived in one parish. They were similar in age and appeared in the same register. An online tree merged them. A small-looking error can move an entire branch, and inheritance research may then follow the wrong relatives.
The examples are illustrative. Sources checked on 16 September 2026. This article concerns Polish law and records.
One match is not enough
Create a separate profile for each candidate: parents, spouse, places, occupation, approximate birth year and documented events. Compare the profiles, asking not just whether the surname fits but whether the remaining facts can describe one person.
The mother’s maiden name or spouse may distinguish the two Jans. The same village is not conclusive either: families moved, and relatives with identical names could live nearby.
Different spellings need not mean different people
AGAD’s indexing guidance discusses historical surname spellings, feminine forms and variations. Searching only the present-day spelling can miss the right record.
The opposite trap is treating every similar spelling as the same family. Preserve the original and record a modern working form separately. Mark suspected clerical errors as hypotheses and seek corroboration. Do not silently alter source wording.
Test the chronology
Arrange events on a timeline. Check appearances after a documented death, plausible ages and consistency between marriages. An age discrepancy need not exclude identity, but it requires explanation.
Do not protect a preferred tree by ignoring an inconvenient record. Keep two hypotheses and identify the document that could distinguish them. Research then answers a question instead of forcing each discovery into the first idea.
Inheritance also requires legal succession
Establishing that two records concern the same person does not establish an inheritance entitlement. Wills, death sequence, declarations and other circumstances may matter. Kinship is only part of the picture.
The appropriate inheritance document establishes an heir’s rights against the third parties specified by law. Genealogy helps prepare evidence and identify gaps but does not replace the court or notary. Separate identification from legal assessment in the report.
What to prepare
- Separate profiles for people with similar details.
- Original surnames and search variants.
- Event chronology and a discrepancy table.
- A supporting document for every accepted family relationship.
Remember
A coherent set of facts and clearly recorded doubts protect against mistakes better than a familiar surname alone.
Sources and references
Official legislation, judgments and institutional materials. The relevant sources are identified below each section.
- AGAD — guidance on indexing historical registers — opens a new windowRelevant guidance and reasoning
- Polish Civil Code — consolidated text, Journal of Laws 2026, item 795 — opens a new windowart. 924–926, 1025 and 1027