[1] Letzi comes from Middle High German and means a hindrance, obstacle, bulwark or frontier fortifications.

[2] In 1331 Konrad Justinger called it stetli Mülenen which implies that a settlement had grown up around the castle and wall.

The Wädenswil and Turn families joined a coalition of nobles that attempted to fight against the growing power of the city of Bern.

After passing through several owners, in 1352 Bern bought the castle and the rest of the Herrschaft of Mülenen.

A Bernese castellan was appointed who managed the military and the high and low courts.