Dominic de Guzmán (1170–1221)

Founder of the Order of Preachers (Dominicans). Dominic de Guzmán, almost exclusively known as Saint Dominic, was a Castilian religious priest and the founder of the Order of Preachers (Dominicans). He is the patron saint of astronomers and natural scientists, and he and the Dominicans are traditionally credited with spreading and popularizing the rosary.