Examples when a country engaged in military operation in another one passed a law essentially inviting the citizens of the latter to become its own?

According to al-Jazeera, today Putin signed a decree that:

“all citizens of Ukraine” be given “the right to apply for admission to the citizenship of the Russian Federation in a simplified manner”.

Previously, a simplified procedure for acquiring Russian citizenship applied only to residents of the self-proclaimed breakaway territories of the Donetsk People’s Republic (DPR) and Luhansk People’s Republic (LPR) in eastern Ukraine, Russia’s TASS news agency reported.

Are there prior examples when such legal invitations have been made during an armed conflict? Particularly to all the citizens of the latter country, which seems to be the case here?