In 1401, the guild of wool merchants in Florence, the Arte di Calimala, announced a competition for a second set of doors for the Baptistery of San Giovanni, located in front of the Florence Cathedral. Two surviving competition panels, one by Filippo Brunelleschi and the other by Lorenzo Ghiberti, exhibit dramatically different styles and compositions although both were based on the same subject—Abraham's sacrifice of his son, Isaac. While we know that Ghiberti was eventually awarded the commission, Brunelleschi's biographer claimed that the competition ended with a tie, and that when the committee decided to split the commission, Brunelleschi withdrew.