When did Galileo invent the military compass?

Answer 1

maybe somewhere around the time of the publication of "The Operations of the Geometrical and Military Compass" which was about 1606.

Answer 2

Galileo did not invent the military compass. The military compass, also known as the mariner's compass, was invented in ancient China during the Han Dynasty (2nd century BC). Galileo Galilei was an Italian scientist known for his work in astronomy and physics during the 16th and 17th centuries.