Initially, Polish authorities took the news of Khmelnytsky's arrival at the Sich and reports about the rebellion lightly. The two sides exchanged lists of demands: the Poles asked the Cossacks to surrender the mutinous leader and disband, while Khmelnytsky and the Rada demanded that the Commonwealth restore the Cossacks' ancient rights, stop the advance of the Ukrainian Greek Catholic Church, yield the right to appoint Orthodox leaders of the Sich and of the Registered Cossack regiments, and to remove Commonwealth troops from Ukraine. The Polish magnates considered the demands an affront, and an army headed by Stefan Potocki moved in the direction of the Sich.