Hilary was born at the beginning of the fourth century. He was elected Bishop of Poitiers in 350. He fought strongly against Arianism and was exiled by the Emperor Constantius. His works are full of wisdom and learning, directed to the strengthening of the Catholic faith and the right interpretation of Scripture. He died in 367. He was declared a Doctor of the Church by Pope Pius IX in 1851.

The theological virtue of hope is symbolized by the colour green, just as the burning fire of love is symbolized by red. Green is the colour of growing things, and hope, like them, is always new and always fresh. Liturgically, green is the colour of Ordinary Time, the orderly sequence of weeks through the year, a season in which we are being neither single-mindedly penitent (in purple) nor overwhelmingly joyful (in white).