From the plaque in front of a small museum:
“Karaites, a nation speaking Turkic, settled in Trakai in the end of the 14th century. The official date of Karaites migration to Trakai is 1397-1398. The name of the nation is derived from Karaites faith. The faith is based on the Old Testament and has Islamic elements. Kenessa (a temple) building of Karaites cult has remained in Trakai..