Below are brief explanations of common attributes given to saints to identify them in art.
St. Benedict is the founder of the Benedictine monastic order.
Saints Cosmas and Damian
Saints Cosmas and Damian are typically portrayed together, as they were brothers (some sources claim twins). They were the patron saints of physicians and therefore closely linked to the Medici, the ruling family of Florence, due to the play on the Medici name (“medici” is the Italian word for “doctors”). They are usually depicted in red togas and red caps. Sometimes, they are shown with surgical tools or ointment jars laying near them, denoting their status as doctors.
St. Catherine of Alexandria
According to Christian belief, St. Catherine of Alexandria was an Egyptian woman of noble birth who was persecuted by Emperor Maxentius. She was to be killed on a spiked wheel, but upon her touch, it broke. Thus, her main attribute in paintings is a spiked wheel. She was subsequently beheaded.
St. Francis (1181/2-1226) founded the Franciscan monastic order. He is generally depicted in his monk’s habit or receiving the stigmata (i.e. the wounds of Christ).
Saint Jerome’s major identifier is his tamed lion, whom he allegedly met while living in the wilderness.
St. John the Baptist
A popular subject among Renaissance artists is St. John the Baptist. St. John the Baptist was believed to be Jesus’ cousin; his epithet derived from his role in Jesus’ baptism. Generally, St. John is recognizable via his animal hair tunic, his processional cross, and his untamed hair.
St. Matthew the Evangelist
Saint Matthew the Evangelist is generally pictured holding a Bible, an allusion to his contribution to the New Testament, the Gospel of Matthew.
St. Miniatus is a Florentine saint, who is regularly depicted in Florentine altarpieces.
St. Paul is identifiable via his long, pointed beard and (usually) bald head. He is also generally holding a sword, an allusion to his martyrdom (he was beheaded by Romans), and a book, a reference to his epistles.
One of the most well known of the saints is St. Peter (for whom the Vatican’s Cathedral is named). According to the Bible, St. Peter led his fellow 12 Apostles after Jesus was crucified, and as the leader of the early Church, he is considered by the Church to be its first pope. He is typically depicted with a set of keys (which has been incorporated into Papal coat of arms, as a nod to its first pope) because Jesus is supposed to have told him that he would give St. Peter the keys to the Kingdom of Heaven (“I will give you the keys of the kingdom of heaven, and whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.” Matthew XVI:19). He also is usually depicted with a short square-shaped beard and holding a book.
St. Vincent of Saragossa
St. Vincent of Saragossa is generally shown carrying a ship and/or a millstone, an allusion to the fact that his body was thrown into the sea after he died. He is also sometimes depicted holding a palm, the universal symbol of martyrdom.
St. Zenobius is a patron saint of Florence, Italy. Allegedly, St. Zenobius saved Florence from the Ostrogoths in AD 405 when he was bishop of Florence. St. Zenobius is most famous for his uncanny ability to bring people back from the dead.