Mongol invasion of Rus'
After the pillaging of Kiev by Andrei Bogolyubsky of Vladimir-Suzdal in 1169, followed by Mongol invasion of Rus' in 1240, the cathedral fell into disrepair. It was also greatly damaged in the 16th century when the Polish–Lithuanian Commonwealth was trying to unite Catholic and Orthodox churches. At this period the cathedral was almost ruined: its roof decayed and a lot of wall paintings had gone.