Leo was born in Etruria and became Pope in 440. He was a true shepherd and father of souls. He constantly strove to keep the faith whole and strenuously defended the unity of the Church. He repelled the invasions of the barbarians or alleviated their effects, famously persuading Attila the Hun not to march on Rome in 452, and preventing the invading Vandals from massacring the population in 455.

Red is the colour of fire and of blood. Liturgically, it is used to celebrate the fire of the Holy Spirit (for instance, at Pentecost) and the blood of the martyrs.