Pope Stephen IX, born as Frederick of Lorraine, served as pope from 1057 to 1058. He was known for his efforts to reform the Church and strengthen its authority. His papacy was marked by a commitment to combating simony, the buying and selling of church offices, and promoting clerical celibacy. During his short reign, Stephen IX also worked to improve relations with the Holy Roman Empire and supported the reforms initiated by his predecessor, Pope Leo IX. His papacy ended with his death in 1058, after which he was succeeded by Pope Nicholas II.