It's funny because criminalisation in Poland is stated as 1815 but Poland was not existing at that time. It's had been divided by three countries (Russia, Germany and Austria-Hungary) three times, last done on 1795 which made Poland inexistent for next 123 years. I wonder which territory was taken into account because there were three different law systems on the three partitions.
Although I suspect it may be coming from the Wikipedia article, or its source (which is in Polish so I can't verify exactly what it says) - reproduced below.
> The Napoleonic Code, introduced in the Duchy of Warsaw in 1808, was silent on homosexuality. After 1815, all three countries that partitioned Poland explicitly declared homosexual acts illegal. In Congress Poland homosexuality was criminalised in 1818, in Prussia in 1871 and in Austria in 1852. Russia's new code of law (called Kodeks Kar Głównych i Poprawczych/Уложение о наказаниях уголовных и исправительных 1845 года) in 1845 penalized homosexuality with forced resettlement to Siberia.
