Traditionally represented as carrying an two keys.
WHY DO CATHOLICS ALLOW REPRESENTATIONS OF SAINTS
In a time when people were largely illiterate images of saints and biblical scenes were used to decorate churches. Popular Saints were often represented to show the people that those who had gone before us were part of our lives of prayer too. It is the part in the Nicene creed – “I believe in the communion of saints”
This is not the communion we refer to when we speak of the Holy Eucharist. It is the communion of a community praying together. As a Church we believe that those who have gone before us pray with us – and just as one might ask a good neighbour to pray for a particular intention – the representation of great saints were points where you might ask a particular saint to pray for you.
Catholicism is strict in its teaching that the saints have ONLY intercessory powers; a power that the living enjoy equally! A saint cannot grant a wish or fulfil a prayer as these powers are reserved to God alone. Even prayers through the intercession of Mary always end with a petition ‘pray for us’ as Mary has no divine powers.
So when a person is concerned about their health, as an example, you can ask St Martin for his prayers just as you might ask any neighbour. This is because St Martin continues to live in as a Saint of Heaven; “the souls of the virtuous are in the arms of God”
Representing saints developed rules; St Peter is always shown carrying two keys, St Paul gets a book and a sword, St John gets a scroll and an eagle, St Mary Magdalene carries a skull and a jar of ointment. St Dominic gets a lily and a star on his brow, St Theresa a scroll and an arrow piercing her heart – we have no idea of what most saints looked like in real life. Their representations are more symbolic than personal. After all, most representations of Jesus are recognisable through his red cloak and a cross inside his halo – his face differs with every artist. He probably was small, swarthy with dark Semitic features and the blond blue-eyed Jesus preferred by many artists would have been a bit freakish in first century Palestine.
The other reason for representing saints is pastoral. Saints often endured terrible conditions but conquered them through faith. The stories would have been inspirational at a time when life wasn’t as easy as it is today in Christian lands.