Queen of the Most Holy Rosary
"Moreover, we may well believe that the Queen of Heaven herself has granted an especial efficacy to this mode of supplication, for it was by her command and counsel that the devotion was begun and spread abroad by the holy Patriarch Dominic as a most potent weapon against the enemies of the faith at an epoch not, indeed, unlike our own, of great danger to our holy religion. The heresy of the Albigenses had in effect, one while covertly, another while openly, overrun many countries, and this most vile off spring of the Manicheans, whose deadly errors it reproduced, were the cause in stirring up against the Church the most bitter animosity and a virulent persecution. There seemed to be no human hope of opposing this fanatical and most pernicious sect when timely succour came from on high through the instrument of Mary's Rosary. Thus under the favour of the powerful Virgin, the glorious vanquisher of all heresies, the forces of the wicked were destroyed and dispersed, and faith issued forth unharmed and more shining than before."
– Pope Leo XIII.
Today, 7th October is the feast of Our Lady of the Rosary, and this stained glass window is the church of St Joseph des Carmes in Paris.