The Coat of Arms of the Augustinian Order dates back at least to the 15th Century.
Its origin remains obscure; however, we can assume that it was made according to the rules of heraldic art. It was adopted by the Order in the 17th century, probably when the Monastery of Dieppe underwent a reform (of its own accord after the Council of Trent 1563). The adoption of the Coat of Arms, then, should be dated between 1625 and 1666 when it appeared on the frontispiece of the Constitutions published that year.
The olive tree symbolizes Mercy. In Greek, "Eleison" also means "have pity" and has the same root as "Elaison" which means both olive tree and olive oil.
The richness of the symbolism of olive oil is apparent throughout the Bible and the Liturgy. It evokes the end of God’s anger, peace, healing, strength. It nourishes and enlightens, is used in anointing, burnt in sacrifice and makes us joyful. It is a sign of gentleness, goodness, love and mercy.
Finally, the olive tree is always green. Its branches are laden with fruit, symbolizing prosperity, fertility and fidelity. Like an olive tree, the Order of the Augustinians ought to be a tree of Peace in the midst of the Church:
The heart is that of St. Augustine, in his ardent search for God. This is the oldest part of the coat of arms.
The hearts of the Augustinians ought to be set ablaze with charity from the fire of the Holy Spirit, as was that of St Augustine and be at the service of the Church through works of Mercy.
The motto "Qui coronat te in misericordia (Ps 102, 4)" represents the essence of the Augustinians vocation: (The Lord…) "Who crowns you with steadfast love and mercy". This could also be read as: "Your crown, your strength is Mercy."