This document provides teaching materials for a history lesson on the Irish Treaty negotiations between October and December 1921. It includes an introduction outlining the aims of an inquiry-focused approach to teaching the topic. The document then outlines a case study approach divided into 4 steps: 1) events between July-October 1921 leading to negotiations, 2) main issues that arose in negotiations, 3) circumstances around signing the agreement, and 4) divisions that emerged in Ireland after. It provides primary sources and historians' perspectives to facilitate student analysis of the key events and issues relating to the Irish Treaty negotiations in 1921.