One of our earlier posts recounted the story told by Roderic, Archbishop of Toledo, about the trial by combat in held in 11th century Spain between the champions of the Roman rite and of the autochthonous Mozarabic rite. The imposition of the Roman rite on Spain was an enterprise pursued by King Alphonse VI, who reconquered Toledo—the ancient capital of the Visigothic kingdom—from the Mohammedans in 1085. As part of his efforts to consolidate his power, he saw fit, like Charlemagne centuries before him, to promote liturgical unity within his kingdom, with the support of Rome and Cluny. The Chronicle of the Cluniac monastery of Sahagún explains:
After rising to the lofty and magnificent royal estate of his kingdom, in the eleventh year of his reign, he [Alphonse VI], amongst other things he very laudably and piously did, procured that in all Spain the divine office be celebrated according to the use of the Roman Church, seeking the approval of the most honourable lord Gregory the Seventh of the apostolic see. 
Alphonse carried out his design of establishing the Roman rite in Spain ruthlessly, despite the setbacks not only of the trial by combat, but also of a trial by fire. The chronicle of Nájera reports:
Thus the aforesaid king Alphonse, after he had taken up the government of the kingdoms, sent emissaries to Rome to Pope Hildebrand, who is called Gregory the Seventh, that he might establish the celebration of the Roman rite in all his kingdom. And so the Pope remembered his cardinal Richard, an abbot from Marseilles, and sent him to Spain. He held a noble and general council in Burgos and ordered that the divine office be done according to the Roman custom in the whole kingdom of the aforesaid king.
In the era 1115, on Palm Sunday [9 April 1077], two knights fought in Burgos, one of king Alphonse for the Roman law and the other a Castilian, namely Lope Martínez de Matanza, for the Toledan law; and the king’s knight was defeated. Moreover, while they were still fighting, a great fire was lit in the middle of the plaza, and two books were thrown therein, one containing the Roman office and the other containing the Toledan office, under this condition: that the office be kept of whichever book might escape the flames unharmed. But since the Toledan [book] made a great leap out of the fire, the king, made wroth, forthwith returned it to the fire with a kick, saying, “The horns of the laws bend before the will of kings”. 
We return to Archbishop Roderic’s chronicle, which recalls the trial by fire thus:
Since a great riot broke out after this [the trial by combat] amongst the knights and the people, it was finally resolved that the book of the Toledan office and the book of the Gallican [i.e. Roman] office would be placed in a great bonfire. After the primate, legate, and clergy ordered everyone to fast, and everyone having made a devout prayer, the book of the Gallican office was consumed by the fire; and, while everyone watched and praised God, the book of the Toledan office jumped out of all the flames of fire, remaining altogether unharmed and untouched by the burning of the fire. But since the king was bold and pertinaciously carried out his will, he was not afraid of the miracle, nor was he persuaded to bend to the supplications. Instead, threatening those who resisted with the death penalty and expropriation, he ordered that the Gallican office be observed in all the lands of his kingdom. And then, while everyone wept and was grieved, he coined the proverb, “Laws go whither kings will.”
And thereafter the Gallican office, which had never before been received, was observed in Spain in the psalter as well as in everything else, even though in some monasteries [the Mozarabic use] was kept for some time, and indeed the [Hispanic] translation of the psalter is still to-day recited in many cathedral churches and monasteries.
One cannot help but admire the fortitude and tenacity wherewith against such powerful forces these doughty Castilians defended the liturgy bequeathed to them by their forefathers Sts Isidore and Leander. Would that more of the faithful had shown the same zeal for the liturgy handed down by their forefathers during the calamitous course of the 20th century liturgical “reforms”!
 El qual, despues que suuio en el alteça e magnifico estado rreal de su rreyno, entre otras cosas muchas que muy loable e rreligiosamente fiço, en el onçeno año de su rreino procuro, suplicando al baron de muy onrrada vida Gregorio setimo en la silla apostolical, que en toda España fuese çelebrado el diuinal ofiçio segun que la iglesia rromana acostumbraba.
 Prefatus itaque rex Aldefonsus postquam regnorum suscepit regimina, nuntios Romam misit ad papam Aldebrandum qui cognominatus est Gregorius septimus, ut Romanum ministerium in omni regno suo constitueret celebrandum. Memoratus itaque papa cardinalem suum Ricardum, abbatem Massiliensem in Yspaniam misit; qui apud Burgensem ciuitatem nobile et generale concilium celebrans diuinum officium iuxta Romanam consuetudinem in omni regno predicti regis haberi mandauit.
Era MCXV.a in Dominica de ramis palmarum apud Burgis pugnauerunt duo milites, unus regis Aldefonsi pro lege Romana et alter Castellanus, scilicet Lupus Martinez de Matanza, pro lege Toletana; et uictus est miles regis. Super quo illis adhuc contendentibus, accenso magno igne in platee medio missi sunt in eum duo libri, unus Romanum officium continens alter uero officium continens Toletanum, sub tali conditione: ut cuius modi liber ignem illesus euaderet, eius officium teneretur. Sed cum Toletanus magnum extra ignem saltum dedisset, mox rex iratus illum in ignem pede reiciens dixit: «ad libitum regum fletantur cornua legum». (Until the introduction of the Anno Domini system in the 14th-15th centuries, years were reckoned in Spain as “eras” starting on 38 BC, considered to be the beginning of the Pax Romana in Hispania.)
 Cumque super hoc magna sedicio in milicia et populo oriretur, demum placuit ut liber officii Toletani et liber officii Gallicani in magna ignis congerie ponerentur; et indicto omnibus ieiunio a primate, legato et clero et oratione ab omnibus deuote peracta, igne consumitur liber officii Gallicani et prosiliit super omnes flammas incendii, cunctis uidentibus et Deum laudantibus, liber officii Toletani illesus omnino et a combustione incendii alienus. Set cum rex esset magnanimus et sue uoluntatis pertinax executor, nec miraculo territus nec supplicatione suasus uoluit inclinari, set mortis supplicia et direptionem minitans resistentibus precepit ut Gallicanum officium in omnibus regni sui finibus seruaretur. Et tunc cunctis flentibus et dolentibus prouerbium inoleuit: «Quo uolunt reges uadunt leges».
Et ex tunc Gallicanum officium tam in Psalterio quam in aliis, numquam ante susceptum, fuit in Hispaniis obseruatum, licet in aliquibus monasteriis fuerit aliquanto tempore custoditum, et etiam translatio Psalterii in plurimis ecclesiis cathedralibus et monasteriis adhuc hodie recitatur.