Excerpts from Books and Wikipedia
"He expanded the papal territory by force of arms and advantageous politicking, and was also a prominent patron of the arts and a reformer of Church missions. However, the massive debts incurred during his pontificate greatly weakened his successors, who were unable to maintain the papacy's longstanding political and military influence in Europe. He was also an opponent of Copernicanism and involved in the Galileo affair." [Wikipedia]