San Martín de Porres y Velásquez was humble and caring soul, so it's a wonder he joined the Dominicans.
Okay, the was an inside joke... but it has something to do with inquisitors.
He was a lay brother of the Order of Preachers, known as Cooperator Brothers. In that time they lay brothers had their own distinct habit. They used the black capuce and scapular. I demonstrated this in one my caricatures. You could say San Martín was the model for it.
Saint Martin was born in Peru in 1579, His father was a Spanish nobleman and his mother a freed slave. At age 11 he became an almoner for the Dominican Friary in Lima. He was eventually put in charge of the infirmary where he was known for his care of the sick and his cures. The superiors dropped the stipulation that no blacks could wear the habit of the Order and in 1603 Martin took vows as a Dominican brother. He was very austere, never ate meat and spent much time in prayer.
He was a friend to St. Rose of Lima and St. John Massias. Died in 1639, many miraculous cures are attributed to him.
He is a patron of Peru, poor people, barbers and people of mixed race.
Sanctus Martinus de Porres, ora pro nobis