Out of the Order, the Founder Flambeau fought for Charles Martel (Charlemagnes father) and Founder Jerbiton took Charlemagne's mage-smiths as apprentices.
Considering the Caroligian vs Merovingian, I wouldn't put it past Tytalus to have been involved on "the other side" of the equation. Also, perhaps the Corruption of House Tytalus had it's roots in Merovingian diabolism? 
Another interesting Chronology tidbit post-merovingian:
789: The Founder Jerbiton meets with Charlemagne, after having adopted a number of apprentices of the emperor’s mage-smith, Carolinus. Charlemagne issues a decree outlawing sorcery and divination, punishable by slavery; and paganism and diabolism, punishable by death. “Benevolent magic” such as that practiced by Jerbiton, is permitted.
Sorcery in this case probably means maleficia, harmful magic.