From the Sinsinawa Dominicans (sinsinawa.org):
The Life and Vision of St. Dominic
Dominic de Guzman was a man with a dream. Born in 1170 in the village of Caleruega in the kingdom of Castile, Spain, he founded a family, the Order of Preachers, that would one day reach out and touch every part of the world. Dominic began as a priest of the Diocese of Osma in what is now northern Spain. He was a canon (clergyman) assigned to the cathedral. His peaceful life was suddenly disturbed by a journey into northern lands. Bishop Diego asked Dominic to accompany him on a mission from King Alfonso VIII to arrange for the marriage of his son. As Dominic traveled beyond the borders of his own country, he encountered for the first time the great need of the people to hear the Word of God preached well and in a way that would respond to their spiritual longing.
Priests at that time were generally not well educated, and many of the clergy, priests, and bishops lived extravagant lives that were scandalous to the people. Dominic soon realized that, in order to be a credible preacher, his life had to be rooted in the Gospel he proclaimed.
Dominic returned to southern France and began to gather other men who shared his dream. Even before the Order of Preachers was officially approved in 1216, Dominic had also established a community of women in Prouilhe who would participate in the preaching mission through dedicating their lives to prayer in community.
By the time Dominic died in 1221, the Order of Preachers was already on mission in France, Spain, Italy, England, Hungary, Poland, Greece, Germany, and Scandinavia. Four monasteries of Dominican Sisters had been established, and plans were under way for expansion.
Today the Order of Preachers is worldwide and includes priests, religious brothers, contemplative nuns, and active sisters as well as thousands of lay people who have dedicated their lives to the Gospel. The dream of Saint Dominic is continuing to be realized in our own time.