The flag of the Isle of Man, or flag of Mann (Manx: brattagh Vannin), is a triskelion, composed of three armoured legs with golden spurs, upon a red background.

The Isle of Man flag has been the official flag of Mann since 1931 and is based on the Manx coat of arms, which dates to the 13th century.

The three legs are known in Manx as ny tree cassyn (“the three legs”). The triskelion is an ancient symbol, used by the Mycenaeans and the Lycians. It is not known for certain why the symbol was originally adopted on the Isle of Man. Before its adoption in 1931, the official flag of the Isle of Man was the Union Flag.

There is also a civil ensign for the Isle of Man. This flag was first authorised on 27 August 1971. Another Manx flag is the flag of the Tynwald, which has flown outside the Legislative Buildings since 1971. Wikipedia