sentences:  Being the Jagiellonian dynasty a constant threat to the Masovian princes, Konrad III tried to limit his contacts with countries hostile to the Kingdom of Poland, like the Teutonic Knights, and even Moscow.However, this didn't avoided another dispute, when after the death of Janusz II on 16 February 1495, his Duchy of Płock was claimed by John I Albert, son and successor of Casimir IV.Initially Konrad III didn't give up to his rights and instantly locked himself in Płock.