Which preposition to use with posen

with Occurrences 2%

Mieroslawsky, who had been one of the leaders of the Polish movement of 1846, had gained much popularity in Berlin; and he seemed fully disposed to combine the movement for the independence of Posen with that for the freedom of Prussia, much in the same way as Kossuth had combined the cause of Hungarian liberty with the demand for an Austrian constitution.

to Occurrences 1%

A victorious Germany would probably reconstitute the Duchy of Warsaw under a German prince; an entirely victorious Russia would probably rejoin Posen to Russian Poland and the Polish fragment of Galicia, and create a dependent Polish kingdom under the Tsar.

Which preposition to use with  posen