You cannot lose a citizenship you never had, and that is the whole difficulty. In a descent claim the loss that matters happened to somebody else, on a date, usually decades before you were born — and it ended the line for everyone below them.

So the question can you lose your citizenship has a second form, and it is the one that decides a claim: did an ancestor lose it, or fail to pass it on, and on what date? Seven things do that across the six countries this site covers. Each one turns on a single date, each date sits in a record somebody can look up, and finding the right one is usually a morning’s work rather than a consultancy’s fee.

The seven breaks, and the date each one turns on

The breakWhere it bitesThe one date it turns on
An ancestor naturalised elsewhereGermany, Italy, Poland, Canada before 1977The naturalisation date, against the next birth in the chain
The line runs through a woman before a cut-offItaly before 1948, Germany before 1975, Britain before 1983The child’s date of birth
A woman lost it by marrying a foreignerGermany before April 1953, Italy under the 1912 law, Britain before 1949, Poland under the 1920 ActThe wedding date
The generation limit was reachedThe UK always, Canada since 2009, Italy since March 2025Your own date of birth, and where your parent was born
A registration was made late, or neverIreland’s Foreign Births Register; Germany’s one-year rule for births abroad after 1999The registration date, against the child’s birth
An adoption, or a birth outside marriageBritain before July 2006, Germany before 1993, and adoption almost everywhereThe date of the adoption order, or of the acknowledgement of paternity
The birth happened before the country didPoland 1920, Ireland 1922, Canada 1947, Italy 1861, Germany 1871Your ancestor’s date of birth, or the date they left

Four of those seven are repairable and three are not, which is the distinction the rest of this post is about. The grandparent rule in six countries is the verdict on whether a line reaches you at all; this is the list of the ways it stops on the way.

Break one: an ancestor naturalised before the next birth in the chain

This is the most common break on the site, and the most expensive to discover late.

For most of the twentieth century, a person who voluntarily became a citizen of another country lost the citizenship they were born with. Germany did this under the Reichs- und Staatsangehörigkeitsgesetz of 1913 and kept doing it until the Act modernising German nationality law came into force on 27 June 2024. Poland did it under the Act of 20 January 1920 and the Act of 8 January 1951 that replaced it. Italy did it under Law no. 555 of 13 June 1912, until Law no. 91 of 5 February 1992 rebuilt the whole regime.

The rule is always the same shape, and the date is always the same date: if the ancestor naturalised before the next person in the chain was born, that next person was never a citizen, and nothing below them is either. Naturalised after the birth, and the child was already a citizen at birth; the parent’s later loss does not reach back and take it away.

Ireland is the exception that readers most need to hear, because it reverses the usual advice: an Irish line does not turn on naturalisation at all. Entitlement through a grandparent under the Irish Nationality and Citizenship Act 1956 turns on where the grandparent was born, and a grandfather who became an American in 1931 is still a person born on the island of Ireland. The naturalisation break, country by country works each of them through, and the record that settles it is the naturalisation file.

Break two: the line runs through a woman before a cut-off

Three countries in this table treated descent through a mother differently from descent through a father, and each stopped on a different date.

  • Italy, 1 January 1948. The Constitution came into force that day. A child born to an Italian mother before it is the case that only a court can recognise.
  • Germany, 1 January 1975. Before that date a child born to a German mother and a foreign father did not acquire German citizenship at birth in the ordinary way.
  • Britain, 1 January 1983. Under the British Nationality Act 1948 descent passed through the father. The British Nationality Act 1981, in force from that date, changed it going forward.

Two of the three have a repair route and one has a courtroom. The grandmother's line sets out all three with the statute and the route, and Italy’s is a court case, not a consular filing.

Break three: a woman lost it by marrying a foreigner

Different rule, different date, and constantly confused with the one above. Here the grandmother had the citizenship and the wedding took it away.

German law is the clearest evidence that this happened, because the repair statute names it: section 5 of the Staatsangehörigkeitsgesetz gives a declaration right to the children of “a mother who lost German citizenship before the child’s birth by marrying a foreigner.” A statute does not write a remedy for a loss that never occurred. Italy’s Law 555/1912 carried a comparable rule; Britain’s ran until the British Nationality Act 1948; Poland’s sat in the Act of 1920.

The date is the wedding, read against the child’s birth. Married after the child was born, and the child was already a citizen. Married before, and in several of these countries the child never was. When a grandmother's wedding ended the line goes country by country, and says which of them repaired it afterwards.

Break four: the generation limit was reached

Some lines do not break on an event at all. They simply run out.

  • The United Kingdom has always been the strictest here: a British citizen by descent generally cannot pass citizenship to a child also born outside the UK. One generation abroad, and that is the end of it. The British line.
  • Canada limited descent to the first generation born outside Canada from 17 April 2009. Bill C-3 changed that on 15 December 2025; for a child born outside Canada on or after that date to a Canadian parent also born outside Canada, the line now holds where “your Canadian parent spent at least 1,095 days in Canada before you were born.” Checked on 15 September 2026 against Immigration, Refugees and Citizenship Canada’s eligibility page, last modified 18 February 2026. The Canadian line.
  • Italy had no limit at all until a decree-law of 28 March 2025, converted with amendments in May 2025, cut recognition to two generations for a person born abroad holding another citizenship. An Italian-born great-grandparent is where that lands.

Germany, Poland and Ireland set no generation limit. What they set instead are the loss rules and the registration rules above and below this one, which is why a German line can run five generations and a British one cannot run two.

Break five: a registration was made late, or never

The cruellest break, because nothing went wrong in the family. A form was filed in the wrong order, or not at all.

Ireland. Citizenship acquired by entry on the Foreign Births Register dates from the date of registration, not from birth. So a parent who registers after their child is born has not passed anything to that child. Before the child is born, not after — and it cannot be repaired afterwards. The Foreign Births Register is the whole rule, and registering on it is the procedure.

Germany. Under section 4(4) of the Staatsangehörigkeitsgesetz, a child born abroad after 31 December 1999 to a German parent who was also born abroad does not acquire German citizenship unless the birth is registered with a German mission within one year.

Both are ordering rules rather than eligibility rules, and both are invisible until the next generation applies. If you take one thing from this post, take this: a registration that was available and was not used, in time, is the break nobody in the family knows about.

Break six: an adoption, or a birth outside marriage

Two different facts with the same effect on a chain, and both are more often repairable than readers expect.

Until the Immigration Act 2014 there was no route for a person born before 1 July 2006 to an unmarried British father; sections 4F to 4I of the British Nationality Act 1981, in force from 6 April 2015, created one. Germany treats the equivalent case under section 5 of the Staatsangehörigkeitsgesetz, which also covers a child who lost German citizenship through a legitimation effected by a foreigner.

Adoption runs the other way. It can create a line into the adoptive parents’ citizenship and end the one from the birth parents at the same time — the German missions list adoption among the grounds on which German citizenship is lost. Which effect applies turns on the country of the adoption order and its date, and this is the point for a lawyer more often than any other break here. Adopted, or born outside marriage.

Break seven: the birth happened before the country did

The last one is not a loss at all. The ancestor never held the citizenship, because there was nothing yet to hold.

Polish citizenship as a modern status begins with the Act of 20 January 1920. Canadian citizenship as a status distinct from being a British subject begins on 1 January 1947. Italy was proclaimed a kingdom in 1861 and the German Empire founded in 1871. A line cannot start above the state it runs from.

Ireland is the exception again, and it matters: the entitlement turns on birth on the island of Ireland, so a grandparent born there in 1919, before the Free State existed, still counts. The cut-offs as a table works through all five, with the Northern Irish case set out beside them.

Which breaks can be repaired, and which cannot

This is the sentence a page paid by the application does not need to write, so here it is plainly.

Repairable, on a route that exists today:

  1. The maternal line before 1975 in Germany, and the related cases — the declaration under section 5 of the Staatsangehörigkeitsgesetz, which runs for ten years from the amending Act’s entry into force in August 2021 and extends to the descendants of the person affected. The declaration route.
  2. The maternal line before 1983 in Britain — registration under section 4C of the British Nationality Act 1981, “Acquisition by registration: certain persons born before 1983”, whose first condition is that “the applicant was born before 1st January 1983.”
  3. Birth to an unmarried British father before 1 July 2006 — registration under sections 4F to 4I of the same Act.
  4. The Italian maternal line before 1948 — not a repair route but a judicial one, and it is the point for a lawyer.

Not repairable, whatever anyone quotes you:

  1. An ancestor’s naturalisation before the next birth in the chain. The line ended in their lifetime.
  2. An Irish registration not made before the child was born.
  3. A German birth abroad after 1999 not registered within the year.

If your break is in the second list, stop here. That is not a paperwork problem and no filing fee solves it. Which claims need a lawyer separates the cases where a professional changes the outcome from the ones where a register takes a form — and a break in the second list is in neither category.

The four dates to find before you pay anyone

In this order, because each one decides whether the next matters.

  1. Your ancestor's date and place of birth#

    The place as it was named on the day, and the state that governed it then. This answers break seven immediately, and it tells you which country’s rule you are reading.

  2. Every naturalisation date in the chain, against the birth that follows it#

    The single record that decides breaks one and, for Canada before 1977, break four. It is also the hardest to find, and where most claims stall.

  3. The marriage dates of the women in the line#

    Breaks two and three both turn on a woman’s dates — her child’s birth against a cut-off, her wedding against her child’s birth. Two dates, and most families have both on a certificate already.

  4. Whether any registration was made, and when#

    Ireland’s Foreign Births Register entry; Germany’s one-year registration for a birth abroad. Ask the relatives before you order anything: an entry made in 1994 changes the answer for everyone born after it.

Four dates. With them, the table at the top of this post gives you a verdict; without them, nobody can, including the people who will quote you a price to try.

The posts below take each break apart on its own — the naturalisation that ended the line, the grandmother whose birth or wedding fell on the wrong side of a date, the adoption, and the ancestor who left before there was a country to leave.