Vatican Notes has several nice articles about the St. Dominic stamps:
(see 1971 VN article); ( see 2017 VN article). A lot of interesting facets of St. Dominic's character are found in the Morning Readings of the Daily Liturgy of the Hours prayers recited on August 8th, St. Dominic's feast day. Below is that reading:
From various writings on the history of the Order of Preachers
He spoke with God or about God
Dominic possessed such great integrity and was so strongly motivated by divine love, that without a doubt he proved to be a bearer of honor and grace. He was a man of great equanimity, except when moved to compassion and mercy. And since a joyful heart animates the face, he displayed the peaceful composure of a spiritual man in the kindness he manifested outwardly and by the cheerfulness of his countenance.
Wherever he went he showed himself in word and deed to be a man of the Gospel. During the day no one was more community-minded or pleasant toward his brothers and associates. During the night hours no one was more persistent in every kind of vigil and supplication. He seldom spoke unless it was with God, that is, in prayer, or about God, and in this matter he instructed his brothers. Frequently he made a special personal petition that God would deign to grant him a genuine charity, effective in caring for and obtaining the salvation of men. For he believed that only then would he be truly a member of Christ, when he had given himself totally for the salvation of men, just as the LORD Jesus, the Savior of all, had offered himself completely for our salvation. So, for this work, after a lengthy period of careful and provident planning, he founded the Order of Friars Preachers.
In his conversations and letters he often urged the brothers of the Order to study constantly the Old and New Testaments. He always carried with him the gospel according to Matthew and the epistles of Paul, and so well did he study them that he almost knew them from memory.
Two or three times he was chosen bishop, but he always refused, preferring to live with his brothers in poverty. Throughout his life, he preserved the honor of his virginity. He desired to be scourged and cut to pieces, and so die for the faith of Christ. Of him Pope Gregory IX declared: “I knew him as a steadfast follower of the apostolic way of life. There is no doubt that he is in heaven, sharing in the glory of the apostles themselves”.
From: Libellus de principiis O.P: Acta canonizationis sancti Dominici: Monumenta O.P. Mist. 16, Romae 1935, pp. 30 ss, 146-`57)