We are told countless times how Christians sought to 'Christianize' the world (with missionaries). When Christianity was brought to people of other faiths or no faith it is now considered a "bad thing" (even when it was done in a completely peaceful manner). It was considered "dominating" these people and purging their culture. Still today Christian missionaries (who are not using the violent force associated with century old practices) who try to proselytize in muslim nations are kidnapped and killed.
I see no reason to open the door of Christian Churches to permit Islamic worship (in denial of Jesus). Until muslims can stem the tide of hate in Islam dominant nations, I am skeptical at best at seeing Islam spread to any nation.
Under Ataulf the Visigoths left (412) Italy and went into Southern Gaul and Northern Spain. They increased their territories in Spain (which was evacuated by the Vandals), acquired Aquitaine, and extended their influence to the Loire valley, making Toulouse their capital. The height of Visigothic power was reached under Euric (466–84), who completed the conquest of Spain. In 507, Alaric II was defeated at Vouillé by the Franks under Clovis, to whom he lost nearly all his possessions North of the Pyrenees. Toledo became the new Visigothic capital, and the history of the Visigoths became essentially that of Spain.Weakened by warfare with the Franks and the Basques and by Byzantine penetration in Southern Spain, the kingdom recovered its vigor in the late 6th cent. under Leovigild and under Recared, whose conversion to Catholicism facilitated the fusion of the Visigothic and the Hispano-Roman populations of Spain. King Recceswinth imposed (c.654) a Visigothic common law on both his Gothic and his Roman subjects, who previously had lived under different codes (see Germanic laws). The church councils of Toledo became the main force in the government, and the royal power was weakened accordingly.
King Wamba, who succeeded Recceswinth, was deposed after a civil war, and thereafter the kingdom was torn by civil strife. When the last king, Roderick, seized the throne, his rivals appealed to the Muslim leader Tarik ibn Ziyad, whose victory (711) in a battle near Medina Sidonia ended the Visigothic kingdom and inaugurated the Moorish period in the history of Spain.
Visigoths (New Advent Catholic Encyclopedia)
One of the two principal branches of the Goths. Until 375 their history is combined with that of the Ostrogoths. Ulfilas (Wulfila) laboured among the Visigoths, translated the Bible into their language, and preached Arianism with great success until prince Athanaric obliged him to withdraw (348). At the invasion of the Huns some of the Visigoths fled with Athanaric into the mountains of Transylvania, but the majority of the people turned to the Emperor Valens with the entreaty to be taken into the Roman Empire. In 376 a force of 200,000 Visigoths crossed the Danube, but oppression by the governors led to a revolt. They traversed the country plundering as they went, and, and defeated Valens in 378 near Adrianople. Valens was slain and his successor, Theodosius, made peace with the Visigoths in 382. His policy was to unite them with the empire by means of national commanders appointed by the emperor. Desirous of maintaining peace, he endeavoured to unite the Arians with those who held the Nicene faith. After the death of Theodosius (395) the Visigoths elected Alaric of the Baltha family as their king. Alaric sought to establish a Germanic kingdom on Roman soil by bringing his people into connection with Roman civilization. In 396 he invaded the Balkan peninsula as far as the Peloponnesus and was given the Province of Illyria. He now turned against the Western Empire, and in 401 entered Italy. He was victorious at Aquileia but after the battle of Pollentia (403) was forced to retreat. In 408 he demanded the cession of Noricum, Illyria Pannonia, and Venetia, in 410 he plundered Rome, and soon after died in southern Italy. His successor Athaulf (410-15) led the Visigoths into Gaul, where the following king Wallia (415-19) gained the land between the Garonne and the Loire. Under the succeeding rulers the kingdom was enlarged, and, during the reign of Euric (466) the Visigothic Kingdom of Toulouse, named after its capital Toulouse, included the southern part of Gaul and a large portion of Spain. The Arian kings found the Catholic Church firmly established in the country; and the Catholics enjoyed toleration until the reign of Euric. The conflicts which then arose have been described by Gregory of Tours as bloody persecutions, but this is exaggerated. Euric was in general just towards his Catholic subjects but took steps against individual bishops and clerics who encouraged religious quarrels and were political opponents of the kingdom. Catholics who fled from Africa found an asylum among the Visigoths and Euric's minister, Leo, was a Catholic.When King Clovis and his Frankish followers accepted Catholicism, Clovis undertook to drive the "heretics" out of Gaul. The Catholic clergy made common cause with the Franks and Alaric II (485-507) took severe measures against them, but was not otherwise a persecutor of the Church. In 507 Alaric was defeated and slain by Clovis. Almost all of Visigothic Gaul now fell to the Franks, the last remnant during the reign of Amalaric (526-31). The seat of government was transferred to Spain where Toledo became the capital.
The ensuing era was fairly peaceful. The Catholics received unlimited tolerance, so that the Church constantly increased in strength while the Visigothic nation and kingdom grew steadily weaker. The nobility enthroned and deposed kings at pleasure; of thirty-five kings, seventeen were murdered or deposed. Arianism, isolated after the destruction of the Ostrogothic and Vandalic kingdoms, constantly declined but was revived during the reign of Leovigild (568-86) His son Hermenigild revolted against him but was defeated and beheaded. Later narratives represent Hermenigild as a martyr for Catholicism, his wife, a Frankish princess, having converted him, but contemporary authorities say nothing of it. Leovigild made a vain effort to win the Catholics by a conciliatory confession of faith drawn up by an Arian synod at Toledo. His son Reccared (586-601) became a Catholic and the Visigoths soon followed his example. With this began the amalgamation of Roman and German elements in Spain. In law and politics the Romans became Gothic; the Goths in social life and religion became Roman. The Catholic Church was the national and established Church, while connection with Rome ceased almost entirely. The court of highest instance was the national council at Toledo. The king appointed the bishops and convoked the council. But the constant struggles of the royal house with the secular and spiritual aristocracy caused the downfall of the nation. From the middle of the seventh century the Arabs were masters of North Africa. In 711 they forced their way into Spain under Tarik. King Roderick was defeated at Jerez de la Frontera, and the Arabs acquired almost the whole of Spain. The Romans and Goths coalesced, forming the Spanish nation which succeeded later in driving the Arabs out of the peninsula.