Erard and Philippa landed in France in January 1216.  On their journey to Le Puy-en-Velay, Erard was arrested by agents of the king of France but managed to escape and get to Champagne.  Erard and his supporters took up a position in Noyers, which Blanche of Navarre then besieged in April 1216.  That same month Erard accepted a truce and submitted the matter to the king of France for arbitration. In July 1216, King Philip II finally heard Erard's suit at Melun, but ruled in Blanche's favor due to the overwhelming evidence she provided:  the barons of the realm had sworn to support Theobald III should Henry II not return from the Holy Land, Theobald III had done homage to the king in 1198, Blanche had done homage to the king in 1201, and Theobald IV himself had made an innovative "anticipatory homage" in 1214.  Blanche even provided numerous letters patent, bearing the seals of the barons who had sworn homage.  Philip II ordained that the barons await the majority of Theobald IV and his assumption of his rights as Count .  Philip II ordered Erard and the barons to seal their own letters patent confirming the court's decision and promising to observe a truce.
Question: How many years before Theobald IV, had Blanche done homage to the king?
Answer: 13