Why is St. Gregory the Great often depicted with a dove?

In most popular paintings of St. Gregory the Great he is seen with a dove, either on his head or next to his mouth, due to a legendary story.

A highly influential pope, St. Gregory the Great is known for a variety of stories and legends that come from accounts of his life.

Miracles abound in these ancient biographies and paint St. Gregory as someone who was inspired by the Holy Spirit.

The dove

It shouldn’t be surprising that St. Gregory is frequently depicted with a dove, which is the most popular way to depict the presence of the Holy Spirit.

St. Gregory was very active in his life and implemented many reforms in the Church and did much to lay a firm foundation that others would build upon.

However, the dove is also referring to a particular legend about his life that someone witnessed.

The Catholic Encyclopedia gives a brief summary of this story:

In art the great pope is usually shown in full pontifical robes with the tiara and double cross. A dove is his special emblem, in allusion to the well-known story recorded by Peter the Deacon (Vita, xxviii), who tells that when the pope was dictating his homilies on Ezekiel a veil was drawn between his secretary and himself.
As, however, the pope remained silent for long periods at a time, the servant made a hole in the curtain and, looking through, beheld a dove seated upon Gregory’s head with its beak between his lips. When the dove withdrew its beak the holy pontiff spoke and the secretary took down his words; but when he became silent the servant again applied his eye to the hole and saw the dove had replaced its beak between his lips.

After his death St. Gregory was often illustrated in this way, highlighting the inspiration he received from the Holy Spirit throughout his life, but also calling to mind this specific episode.

For this and many other reasons St. Gregory was named, “the Great.”