War of the Succession of Champagne

In the Holy Land, Henry was crowned king of Jerusalem and - to reinforce his legitimacy - married for the second time to queen Isabella, second wife and widow of Conrad of Montferrat, despite the fact that her first husband (from whom she had been forced to separate) was still alive.

Blanche of Navarre, however, proved to be an incredibly strong and efficient regent, and had devoted herself for the past 15 years to ensuring the legal status of her son Theobald IV as rightful heir.

Blanche was aided in securing her powerbase during the first few shakey years of her regency by the fact that so many lords and knights of the county, who might have posed a challenge to her, had left to fight on the Fourth Crusade from 1202 to 1204.

Further, while Theobald IV was still an underaged youth of 13 years, he had acquitted himself so valiantly in combat at the decisive Battle of Bouvines that King Philip II threw his full support behind him (though this was also the culmination of over a decade of Blanche cementing an alliance with the monarchy, through financial ties and homage).

Apart from various sieges, during the early part of the conflict Erard and his rebel barons attacked merchant caravans traveling to the Champagne fairs at Troyes and Bar-sur-Aube.

During the later years of the war, therefore, Erard would agree to truces with Blanche that would last weeks or months at a time, in order for the trade fairs to occur unmolested.

Nonetheless Theobald I lost Rosheim again when a pro-Frederick II uprising in the city killed the Lorraine garrison (massacring them in their cellars after inviting them down to sample their wines).

With the aid of Duke Odo III of Burgundy and Count Henry II of Bar, Countess-Regent Blanche rode with her army to Lorraine's capital of Nancy in 1218 and burned the town.

Duke Theobald I of Lorraine surrendered Amance by the end of May 1218, and officially renewed his fidelity to Blanche on June 1, at which point the rebellion largely collapsed and rebel barons started making their own separate peaces.

Two months later in May 1222, Theobald IV reached the age of maturity and began his reign as count, and the triumphant Countess-Regent Blanche withdrew to the Cistercian convent of Argensolles for her retirement.

Blanche and Theobald IV had centralized comital authority within Champagne, reining in the rebellious local barons and ending any pretensions of collegiate rule in the county.

Theobald IV promptly divorced Gertrude as soon as he came of age and peace was secured, terminating their brief two-year-long and childless marriage, in order to marry Agnes of Beaujeu.

Theobald IV's rule was initially marked by a series of misfortunes: he was accused of abandoning King Louis VIII at the siege of Avignon (1226), costing him the royal alliance he had relied on to secure his inheritance.

The conflict with the County of Bar prompted the more powerful Duchy of Burgundy to invade Champagne from the south, led by Duke Hugh IV (his father Odo III, Countess Blanche's staunch ally, had died in 1218).

The situation reached its nadir in 1233, when Henry II's elder daughter Queen Alice of Cyprus threatened to reprise the succession war of Theobald IV's minority yet again.