Happy Feast of St. Dominic!

Today is the liturgical feast of St. Dominic de Guzmán, founder of the Ordo Praedicatorum. Dominic died on August 6, 1221 at the convent of San Nicolò delle Vigne in Bologna.

Why is St. Dominic's feast celebrated today and not on the 6th? Gregory DiPippo has an informative post on the history of the feast of St. Dominic at the New Liturgical Movement that explains this and a few other things.