Why Do We Say 'Wear Your Heart on Your Sleeve'?
The answer may come from medieval jousts
We use the phrase "wear your heart on your sleeve" in a casual way to say that we are showing our intimate emotions in an honest and open manner. But why are we "wearing" our emotions? And why a sleeve? Before getting to the heart of this matter, we should turn to the first recorded use of the expression, which is in William Shakespeare’s Othello.
In the Bard’s tragedy, it is none other than the dishonest and villainous Iago who speaks the words to his confederate Rodrigo:
For when my outward action doth demonstrate / The native act and figure of my heart / In complement extern, 'tis not long after / But I will wear my heart upon my sleeve / For daws [birds] to peck at: I am not what I am.
Iago's imagery effectively conveys his belief that when what he feels in his heart is openly revealed, he will become vulnerable to attack. But why did Shakespeare choose the image of a heart upon a sleeve of all things? How did such a turn of phrase come about? Quite possibly, it originated in medieval jousts.
In the Middle Ages, sleeve not only referred to a part of a garment covering the arm but to a piece of armor for covering and protecting the arm. When participating in a joust, knights would often dedicate their performance to a lady of the court and wear something of hers, such as a scarf or ribbon, around their sleeve of armor, which indicated to the tournament's spectators which lady the knight favored. This chivalrous and affectionate gesture may be the source of the saying "wear your heart on your sleeve."
But, alas, this is mere conjecture since evidence is lacking that shows the phrase was used in reference to a knight outwardly displaying who his object of affection was. The only certainty is that by the 17th century, a figurative meaning of the phrase existed, as attested by Shakespeare's use, to express emotional honesty and openness.