The Earl of Cholmondeley refused to wear a helmet despite the warnings of his friends, as he was headstrong. He had the motto "Virtus tutisima caffis (Virtue is the surest helmet).
An unspecified amount of time after he came up with the motto, he met his end. He fell off his horse, a common footsoldier kicked him in the head and he lost his mind as he didn't wear a helmet. He walked straight into the River Thames wearing full plate armor (aside from the lack of a helmet) and quickly sank to the bottom.