It began when a Swiss Confederation force of 1,500 infantry archers, led by Werner Stauffacher, ambushed a group of Austrian soldiers of the Holy Roman Empire under the command of Duke Leopold I of Austria near the Morgarten Pass.

The Confederates prepared a road-block and an ambush at a point between Lake Aegeri and Morgarten Pass where a small path led between the steep slope and a swamp.

When about 1500 men attacked from above with rocks, logs and halberds, the Austrian knights had no room to defend themselves and suffered a crushing defeat, while the foot soldiers in the rear fled back to the city of Zug.

A chronicler described the Confederates, unfamiliar with the customs of battles between knights, as brutally butchering everything that moved and everyone unable to flee.

Within a month of the battle, in December 1315, the Confederates renewed the oath of alliance made in 1291, initiating the phase of growth of the Old Swiss Confederacy.

The victory of the Confederates left them in virtual autonomy and gave them a breathing-space of some sixty years before the next Habsburg attack resulted in the Battle of Sempach (1386).

In 1766 the governments of Oberägeri and Unterägeri (at the time known as Wilägeri) became involved in an open fight during local parliamentary sessions, and the two municipalities split in 1798.

[4] The municipality is located in the eastern pre-alpine, high valley on the northern shores of the Ägerisee at an elevation of about 724 m (2,375 ft).