Dominic (1170 - 1221) is the founder of the Order of Friars Preachers, also known as the Dominicans.
The early part of his priesthood was spent in prayer and penance.
Throughout his ministry he came into frequent contact with the growing Albigensian and Cathar heretical sects, which were gaining in prominence in southern France.
While some in the Church used physical means to stamp out the heretical movements, Dominic chose peaceful means: that is, the establishment of communities dedicated to sacred learning, preaching and praying.
His labours to educate those who were ignorant of the full body of the Christian faith had a deep and lasting impact on the peoples of Europe, Asia and the Americas. A contemporary of Saint Francis of Assisi, Dominic refused a bishopric three times, and is a model of humility and zeal for us all.
"The mouth of the righteous is exercised in wisdom: and his tongue will be talking of judgement: the law of his God is in his heart." (The day's Introit, page E 97, The People's Anglican Missal.)
The above picture is El Greco's (Doménikos Theotokópoulos) oil on canvas entitled "Saint Dominic in Prayer."
Books worth considering
Saint Dominic: Preacher of the Rosary & Founder of the Dominican Order
Early Dominicans: Selected Writings
Praying With Dominic (Companions for the Journey)