Arise O Lord and judge thy cause. A wild boar has invaded thy vineyard!
~ Leo, excommunicating Martin Luther.

Pope Leo X was an antagonist in the 2003 film Luther.

In 1513 Giovanni di Lorenzo de' Medici was elected Pope. As the Pope began his reign Cardinal Thomas Cajetan expressed hope to Girolamo Aleandro that after the reigns of Alexander VI and Julius II that Leo would restore the church to its former glory.

The Pope for his part wanted to continue on with the building of the new St. Peter's Basilica. When Albert of Mainz wanted to become a Bishop of a third German town, Leo told him that he would need to pay for that privilege. Bankers loaned Albert the money to pay Leo the money required. Leo in turn sent the indulgence salesman Johann Tetzel to work over the German towns in order to gain funds so that Albert could pay back the loans.

Meanwhile a young German theologian named Martin Luther became disgusted with the whole idea of indulgences being sold. He posted his 95 theses on the door of a local Cathedral, and sent a copy to Albert. Albert sent the letter and the 95 theses he received on to Leo.

Leo was not happy that a man he considered to be a drunk little German monk was making so much trouble and putting such a dent in the indulgence business. Leo ordered his people to, "sober him." Cajetan and Aleandro tried to get Luther to recant but they were unsuccessful.

Luther's ideas continued to spread across Germany, reaching people from all walks of life. When Frederick the Wise refused to hand over Luther a group of officials led by Aleandro rode out to meet Leo while he was hunting and informed the Pope that Frederick refused to surrender Luther to the church. Leo then decided to excommunicate the German monk and order his works be burned.

After the Diet of Worms where Luther stood up to both the church and Emperor Charles V, Luther was kidnapped by Frederick to keep Leo and his people from murdering the young German monk. Luther stayed in hiding for about a year until a series of uprisings forced him to come out of hiding and confront extremists who were using his words to incite violence.

Meanwhile Leo X died. By then the church was in even worse shape than when he had been elected. Cajetan noted that Leo had left the church was heavily in debt, and that Leo had done nothing to restore the spiritual life of the church. He ruefully noted that Leo had been a spiritual dwarf, that the church had needed a leader like Martin Luther.