<a href="https://en.wikipedia.org/wiki/Treaty_of_San_Germano" id="mwLA" rel="mw:WikiLink" title="Treaty of San Germano">Treaty of San Germano</a> is signed at <a href="https://en.wikipedia.org/wiki/Cassino" id="mwLQ" rel="mw:WikiLink" title="Cassino">San Germano</a> between Holy Roman Emperor Frederick II and Pope Gregory IX. A Dominican named Guala is responsible for the negotiations.