Ingravescentibus Malis §15

¹⁵ Nor are there lacking men famous as to doctrine and wisdom who, although intensely occupied in scientific study and researches, never even for a day fail to pray fervently on bended knee, before the image of the Virgin, in this most pious form. Thus kings and princes, however burdened with most urgent occupations and affairs, made it their duty to recite the Rosary.