The waning loyalty of the Cossacks, and the "szlachta's" arrogance towards them, resulted in several Cossack uprisings against the Polish–Lithuanian Commonwealth in the early 17th century. Finally, the King's adamant refusal to accede to the demand to expand the Cossack Registry prompted the largest and most successful of these: the Khmelnytsky Uprising, that began in 1648. Some Cossacks, including the Polish "szlachta" in Ukraine, converted to Eastern Orthodoxy, divided the lands of the Ruthenian "szlachta", and became the Cossack "szlachta". The uprising was one of a series of catastrophic events for the Commonwealth, known as The Deluge, which greatly weakened the Polish-Lithuanian Commonwealth and set the stage for its disintegration 100 years later.