I finished Adam Zamoyski's "Poland" recently, and he mentions that Poland-Lithuania had a significant enough Armenian population to make one of its five law codes in Armenian. One of the law codes was Hebrew and, well, Zamoyski spends a lot of time talking about what happened to Poland's Jewish population well into the 20th Century. But the Armenians just kind of, disappear from the narrative.
What happened to them?
After partitions majority of polish Armenians became citizens of Austrian Empire, because they were lived in territories which later become known as Galicia. Lviv was the center of their cultural life. Some of them settled in Bukovina, but majority remained in polish territories. At the end of the 19th century they were heavily polonised and became part of polish intelligentsia or aristocracy. There was about 5000 polish Armenians in independent Poland and 1000 in Bukovina. They were all polish speaking, except of the small community in Kuty on the Cheremosh, because their inhabitants were the last wave of Armenians arrived in late 18th century from Moldavia (eventually they were also polonised, because after 1945 they were resettled to polish territories on the west - Kuty became part of USSR - today only 10 people can still speak Kuty dialect of armenian). Significant group of Armenian refugees from Russia, Turkey and Persia came to Poland before the war, they were living mostly in Warsaw and Łódź.
Due to their physical similiarity with ashkenazi Jews there were persecuted by Germans during 2nd World War. But also preparing false Armenian records in parish registers was one of the way to rescue Jews. Because most of polish Armenians was part of inteligentsia and were living in Lviv and its surroundings they were persecuted and killed by Soviets. Also many of them, mainly from Pokuttya, were killed by Ukrainian Insurgent Army.
After the war polish Armenians were resettled to newly acquired polish terriotires, mainly on Silesia. Throughout first years after the war, there was almost no effort, both from the state but also armenians themselves, to cultivate or prevent their armenian identity and culture, but in 1980 Circle for Interest in Armenian Culture was created. Later another also another organisations were created.
After collapse of communism Poland was open for new armenian immigration from Armenia, which was struggling with war and natural disasters. Couple thousands of Armenians arrived to Poland, mainly to Warsaw. But there is clear cultural distinction between old, polonised community and new arrivals.