The Blessed Virgin and the Order of Preachers

The Vision of the Dominican Habit, Fra. Angelico

Article: Devotion to Mary Among the Dominicans in the Thirteenth Century, by Denis Wiseman, O.P.

I really enjoyed this article by Denis Wiseman, professor at the Dominican House of Studies in Washington, D.C., about early devotion to the Blessed Virgin among the friars of the Order of Preachers, including the pious traditions and beliefs about Mary's gracious protection of the Order as well as the early development of the Order's distinctive Marian character. Also, a discussion on the legends about the origin of the Dominican Habit and its connection to the Blessed Virgin:

Jordan's "Libellus" recounts Mary's role in bringing Reginald, a master of theology and dean of the cathedral chapter at Orleans, to the Order. During a serious illness in 1218, Our Lady healed him and, then, according to Jordan's account: "showed him the whole habit of the Order." The "Legenda Petri Ferrandi," composed by the Spanish Dominican, Peter Ferrandus, between 1235 and 1239, records the event, with the words of Mary: "Then she showed him the habit of the Order of Preachers. 'Behold,' she said, 'this is the habit of your Order.'"

...Taken literally, Jordan [of Saxony] and [Peter] Ferrandus may mean only that Mary indicated the order which Reginald should enter by showing its habit. However, these texts have come to be understood as meaning that Mary gave Reginald a new habit or an additional element to the habit. ...The tradition that Mary either gave the entire habit or the scapular has been persistent in the Order. Stephen Salanhac, who died in 1291, describes Mary as the felix huius ordinis vestiaria, "the happy clothier of our Order."

And, of course, the connection between Mary and preaching:

... perhaps the most powerful image for Dominicans is the association of Mary with the preaching mission. In the Dominican House of Studies in Washington, D.C., the Priory of the Immaculate Conception, a figure of the pregnant Virgin stands above the lectern illustrating that she is the model for those who bring forth the Word.