The traditional Mozarabic rite in Hispania was suppressed and substituted with the Roman rite principally through the efforts of Alphonse VI, King of Leon, Castile, Galicia, and Portugal, soi-disant Emperor of all Spain, with the support of Pope St Gregory VII and the Cluniac congregation. Such a liturgical revolution was by no means easily achieved, however, as is evident in the chronicle written by Archbishop Roderic of Toledo:
The clergy and people of all Spain were troubled, for they were compelled to take up the Gallican [i.e., Roman] Office by the legate [Richard] and king [Alphonse]. On the appointed day, when the king, the primate, the legate, and a great multitude of clergy and people were assembled, there was a long quarrel: the clergy, the knights, and the people firmly resisted any change in the Office, whereas the king, counselled contrariwise by the queen, thundered terrible threats. Finally, on account of the obstinacy of the knights, it was decided that this dispute would be settled by combat. Two knights were chosen, one by the king that he might fight for the Gallican Office, the other by the knights and the people to fight for the Office of Toledo. The king’s knight was defeated forthwith, and the people rejoiced because the victor was the knight of the Office of Toledo. But Queen Constance persuaded the King not to abandon his designs, saying that the duel was not lawful. The knight who fought for the Office of Toledo was of the house of Matanza, near Pisorica, and his family still exists to-day.
[…] clerus et populus tocius Hispanie turbabatur, eo quod Gallicanum officium suscipere a legato et principe cogebantur; et statuto die rege, primate, legato, cleri et populi maxima multitudine congregatis, fuit diutius altercatum, clero, milicia et populo firmiter resistentibus ne officium mutaretur, rege a regina suaso, contrarium minis et terroribus intonante. Ad hoc ultimo res peruenit militari pertinacia decernente, ut hec dissensio duelli certamine sedaretur. Cumque duo milites fuissent electi, unus a rege, qui pro officio Gallicano, alter a milicia et populis, qui pro Toletano pariter decertarent, miles regis ilico uictus fuit, populis exultantibus quod uictor erat miles officii Toletani. Set rex adeo fuit a regina Constancia stimulatus, quod a proposito non discessit, duellum iudicans ius non esse. Miles autem qui pugnauerat pro officio Toletano, fuit de domo Matancie prope Pisoricam, cuius hodie genus extat.
Roderic of Toledo, De Rebus Hispanie, book VI, chapter XXVI