Complex sentence: The Town Parish Church in Łańcut is also connected with the castle, as it was founded by the estate owners, and the splendid Potocki family crypt was used as their burial ground.
Split into simpler sentences: The Town Parish Church in Łańcut is also connected with the castle, as it was founded by the estate owners. The splendid Potocki family crypt constructed beneath the church was eventually used as their burial ground.