Gregory X, born Teobaldo Visconti around 1210 in Piacenza, was a Cistercian who served as the head of the Catholic Church from 1271 until his death in 1276. His election followed the longest papal vacancy in the history of the Church, which had lasted from 1268 to 1271. During his papacy, he oversaw the Second Council of Lyon and established significant new rules for the conduct of future papal elections. He is recognized as a blessed in the Catholic tradition.