Gregory IX
Ugolino di Conti · 1227 – 1241
Established the papal Inquisition, published the first official collection of Church law, and clashed bitterly with Emperor Frederick II.
Ugolino was already an elderly cardinal when he became pope in 1227. He was a nephew of Innocent III and shared his uncle's expansive view of papal power. His first major act was excommunicating Emperor Frederick II for repeatedly delaying his promised crusade. The two fought for the rest of Gregory's pontificate. Gregory formalized the Inquisition in 1231, assigning Dominican and Franciscan friars to investigate heresy, a move that would cast a long shadow. He also commissioned Raymond of Penyafort to compile the Decretals, the first systematic collection of papal law, which became the foundation of canon law for centuries. He canonized Francis of Assisi, Elizabeth of Hungary, and Anthony of Padua. Despite his advanced age, he was combative to the end, dying in 1241 while Frederick's army was at the gates of Rome.
The Inquisition Begins
Gregory did not invent the prosecution of heresy, but he institutionalized it. By taking it out of the hands of local bishops and handing it to the mendicant orders, he created a centralized system that could operate across borders. It was effective, and it caused enormous suffering over the following centuries. Both things are true.
Ordering the Law
The Decretals of Gregory IX organized centuries of scattered papal rulings into a coherent legal code. It was the Catholic Church's equivalent of codifying common law, and it remained the backbone of canon law until 1917.