On this day, in the year 1267, Pope Clement IV issued the Bull "Consurgit in nobis", granting the request of Blessed John of Vercelli to give official approval of the Dominican Office. From "A History of the Dominican Liturgy, 1944, pp. 197-198:
"We are filled with the greatest spiritual joy, when we behold those who are dedicated to the divine service bonded together in virtuous harmony. Especially when we perceive them desiring, for the honor of the Divine Name, that the cause of holy unity should prosper among them to such an extent that their state in life may enjoy not only lasting peace and tranquil devotion, but also appear always well-ordered - as propriety demands. For both reasons there is a great cause for congratulations, since unity of faith and pious deeds so shine forth in these religious that this renowned Order may assume this praise: it possesses every adornment of surpassing beauty, and it is entirely free of every blemish.
Dominican Office crica 1254-1256
"Gladly have we heard your petition. When your illustrious Order had, by the grace of Christ, spread its branches from sea to sea, the Divine Office was not uniformly observed throughout the Order owing to the various customs of the different provinces. Wherefore, as true servants of God and sincere lovers of sound unity, you realized with commendable foresight that this diversity of observance would be prejudicial to devotion or even perhaps become an occasion of grave scandal. So you unanimously commissioned Our beloved son, Friar Humbert, former general of the Order, to make the said office uniform, that everywhere throughout the world the entire Order might reverently and humbly observe this uniformity. When at length Humbert had completed a skillful and befitting arrangement of the ecclesiastical office, you carefully examined the work, and then decreed in three successive general chapters that the arrangement of the office should be observed throughout your Order. For this reason, you have humbly petitioned Us to add the authority of Apostolic protection to this office.
"We being favorable to your supplications and holding as valid and lasting the arrangement of the office, do therefore decree and confirm by Our Apostolic authority that the aforesaid arrangement is to be followed in all your houses and by the protection of these presents We do strengthen it.
"We strictly forbid anyone, without the permission of the Apostolic See, to change anything in the aforesaid office against the tenor of Our Confirmation and Constitution and that of the aforesaid arrangement.
"To absolutely none, therefore, is it permitted to disregard this confirmation, constitution and prohibition, etc..
"Given at Viterbo, on the 7th day of July, in the third year of Our Pontificate (1267)
Happy 750th Birthday to the Breviarium juxta ritum ordinis prædicatorum!!