St. Dominic was born at the end of the 12th century into a wealthy family. His mother was Blessed Joan of Aza. Dominic was a brilliant student and joined the Benedictine order. He had a love for the poor and sold all his possessions to feed the hungry. Dominic is famous for fighting the Albigensian Heresy which said all of the physical world is bad and the spiritual world needs to be freed from it. While Dominic embraced poverty and the fallen nature of man, he was able to convince the Albigensians through his preaching that the material world was good. The heresy was rendered all but obsolete. 

St. Dominic then started his own order called the Order of Preachers (OP) whose mission was to preach truth in the face of heresy. He is also attributed to receiving the rosary from the Blessed Mother in a vision in 1214. From that time on, the rosary has become the most popular devotion in the Catholic Church. St. Dominic died from fever at the age of 51 and is the patron saint of astronomers.