The dedication of Saturday to Mary in the liturgy began in Carolingian times, with the English monk Alcuin of York (735-804), a leading scholar and teacher at the court of Charlemagne. We don't know why Alcuin decided to include Marian intentions in the Saturday liturgy, but in the centuries that followed, theologians and liturgists such as Humbert of Romans, a French Dominican friar (who served as the fifth Master General of the Order of Preachers from 1254 to 1263) offered at least seven reasons for this choice:
1 - Saturday is the day blessed by God more than the other days. God blessed the seventh day (cf Gn 2:3), and Mary is "blessed among women" (Lk 1:42).
2 - Saturday is the day sanctified by God, and Mary is "full of grace" (Lk 1:28); it is therefore right to dedicate the holy day to the All-Holy Woman. Alternatively, Saturday is the day on which God completed the work of nature, and in Mary, God completed the work of grace.
3 - Saturday is the day when God, after the work of creation, rested (cf. Gen 2:2), but God's true "rest" is Mary, to whom the liturgy applies Sir 24:8: "He who created me rested in my tent", because God rests in a soul who satisfies him, namely Mary. The Bible also says that God rested in his tabernacle (Ps 18:6). Humbert says, "Saturday and the Virgin are thus associated: Saturday is the day and Mary is the place where God rests."
4 - Just as Saturday is the gateway to Sunday, Mary was the gateway through which Christ entered the world.
Ignazio Calabuig
Il culto di Maria in occidente, in Pontificio Istituto Liturgico sant'Anselmo.
Scientia Liturgica, sotto la direzione di A.J. Chupungco, vol V, Piemme 1998. pp. 342
(to be continued tomorrow, September 2)