text: A pope with this name led an Italian league that fought off Saracen pirates at the Battle of Ostia, and ordered the construction of a wall around a namesake "City" that included the Borgo and the Vatican.
full_question: A pope with this name led an Italian league that fought off Saracen pirates at the Battle of Ostia, and ordered the construction of a wall around a namesake "City" that included the Borgo and the Vatican. Another pope of this name tried to organize a crusade against Selim I, but was better known for his high spending and ownership of a white elephant named Hanno. The most recent pope with this name issued an encyclical calling for capitalism to address the concerns of the working class, titled Rerum Novarum. The successor of Julius II had this name, and his construction of St. Peter's Basilica led to the sale of indulgences, criticism of which led him to issue the papal bull Exsurge Domine. For 10 points, name this papal name whose tenth holder was an opponent of Martin Luther.
first_sentence: A pope with this name led an Italian league that fought off Saracen pirates at the Battle of Ostia, and ordered the construction of a wall around a namesake "City" that included the Borgo and the Vatican.
raw_answer: Leo [or Leo IV; or Leo XIII; or Leo X]