Complex sentence: The building was funded by Michał Kazimierz Pac and its construction was unfortunately terminated by his death (1682) in 1684 which prevented creating the main altar according to the original plan.
Split into simpler sentences: The building was funded by Michał Kazimierz Pac. The decoration works were unfortunately terminated in 1684 due to the founder's death in 1682, which prevented creating the main altar according to the original plan.