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The Merovingian Dynasty was a Frankish line of kings who ruled in Western Europe from AD 476 to 752. By the end of the 5th century, the Western Roman Empire and the influence of Greco-Roman culture were in decline. The Roman Empire had lost its hold on most of Western Europe. From the capital in Constantinople (modern Istanbul), the Eastern Roman Empire was focused on defending against Arab/Islamic invaders from the East. Out from under the thumb of Rome, and with less pressing threats from invaders, Western Europe began to come into its own politically, and Christianity in Western Europe began to develop as well.
At this time and for several centuries to follow, Gaul was the largest and most important state in Western Europe. It encompassed modern France and Luxembourg as well as significant portions of Switzerland, northern and central Italy, Germany, and the Netherlands. Gaul fell to the Franks, a Germanic tribe, in 486. The Merovingian Dynasty, named for the Frankish King Merovech, continued to expand their kingdom. In 496, Merovech’s grandson, King Clovis I, was baptized as a Christian. (His wife was Catholic, and she had been trying to convert him. Before an important battle that he feared he might lose, Clovis asked the aid of his wife’s God. After victory in battle, he “converted.”)
Clovis’s conversion had significant historical impact but seems to have had very little personal impact. Clovis and his forces were still quite willing to use treachery and brutality to defeat any opposition. As a Catholic convert, Clovis was loyal to the Nicene Creed. Although Arianism had been popular among Germanic peoples, Clovis led his people to accept the orthodox understanding of the Person of Christ and also used this theological disagreement as motivation (or pretext?) to expel the Arian Visigoths from Southern France.
As loyal Catholics, the Merovingian rulers were allied with the Pope and became promoters of Catholic Christianity. Although the Merovingians were harsh and even barbaric in their rule, their alliance with and promotion of Roman Catholicism resulted in at least a nominal acceptance of orthodox Christianity throughout Western Europe and even led to the spread of Christianity to England.
The harsh practices of the Merovingian Dynasty in the 6th and 7th centuries were detrimental to the Church. The Merovingians viewed the Church as a tool to be used for their own purposes. They regularly appointed laymen as bishops and sold church offices. Pope Gregory tried to institute reforms, but these were resisted. Finally, in 752 Pope Zachary deposed King Chideric III, ending the Merovingian Dynasty. Pope Stephen II (Zachary’s successor) crowned Pepin the Short king of Gaul. Pepin was the first king of the new Carolingian Dynasty.
When considering the impact of the Merovingian Dynasty, it might be easy to slip into cynicism. This is one instance in which orthodox Christianity (at least orthodox in respect to the Nicene Creed) was spread by ungodly political and military means. However, we must remember that God can use any event and any ruler—even those who have no genuine allegiance to Him—to accomplish His ultimate goal without divine approval of the means (see Isaiah 10:5–19). What the Merovingian kings did with sinful motives God used to spread (at least a nominal) orthodox Christianity throughout Western Europe and prepared the way for the gospel to be proclaimed in England. Just as Joseph pointed out to his brothers who sold him into slavery that what they meant for evil God used for good (see Genesis 50:20), the progeny of English Christianity can be thankful for the influence of the Merovingian Dynasty while acknowledging that many of the means used to spread Christianity were counter to the spirit of it.
In the 1982 book Holy Blood, Holy Grail and the 2003 book The Da Vinci Code, the authors concoct a myth that the Merovingian kings were actually physical descendants of Jesus Christ through a relationship with Mary Magdalene. This is a baseless hoax. While the Merovingian kings claimed divine support for their dynasty, there is no historical record of them claiming to be of the bloodline of Jesus Christ. Further, there is absolutely no biblical or historical evidence of Jesus being married or having children.