A feather in one's cap
A symbol of honour and achievement.
The placing of a feather in a hat has been a symbol of achievement that has arisen in several cultures, apparently independently. The English writer and traveller Richard Hansard recorded it in his Description of Hungary, 1599:
"It hath been an antient custom among them [Hungarians] that none should wear a fether but he who had killed a Turk, to whom onlie yt was lawful to shew the number of his slaine enemys by the number of fethers in his cappe."
The Native American tradition of adding a feather to the head-dress of any warrior who performed a brave act is well known.
The figurative use of the phrase 'a feather in his hat' was in use in the UK by the 18th century; for example, in a letter from the Duchess of Portland to a Miss Collingwood, in 1734:
"My Lord ... esteems it a feather in his hat, that ..."
The children's rhyme Yankee Doodle is the best known use of the phrase.
Yankee Doodle went to town,
Riding on a pony;
He stuck a feather in his cap,
And called it macaroni.
There are many version of the lyric. It has been suggested that this version originated with the British forces in the American War of Independence, in an attempt to mock the revolutionary militia. 'Doodle' was 18th century British slang for simpleton (a.k.a. noodle) and 'macaroni' was slang for a dandy or fop. The latter originated with the Macaroni Club, a group of London aesthetes who were anxious to establish their sophistication by demonstrating a preference for foreign cuisine. The thinking behind the theory is that the Yankees were so stupid as to believe that putting a feather in one's cap would make them appear fashionable.