In 1200, Stephen's brother Geoffrey joined the
Fourth Crusade. He spent much of the next two years preparing, but he died just before Easter 1202. Among his pious acts of preparation was the grant of a charter to
Le Mans Cathedral promising comital protection for its property at
Courgenard in the Perche. Stephen swore to respect Geoffrey's promise to Le Mans. He had committed to the crusade by January 1202, when he mortgaged his properties at
Langeais to cover his expenses. Geoffrey, on his deathbed at
Le Theil, entrusted command of the Percheron contingent to Stephen. In May 1202, King John stood as surety for a loan to Stephen from the
Templars and
Hospitallers. During the interval between his brother's death and his departure, Stephen seems to have governed the county of Perche again. After his departure, Geoffrey's widow Matilda took over the regency for her minor son,
Thomas. In June, Stephen and the Percheron contingent joined the main French force massing at Chartres. He made several religious bequests before departing, including the endowment of a memorial
requiem mass for himself to be celebrated in
Chartres Cathedral annually on the anniversary of his death. In June, he also confirmed his sister-in-law's endowment of an annual requiem for his brother. He probably travelled in the company of his cousin Count
Louis I of Blois. Stephen made the rendezvous at
Venice in October 1202, but he was physically incapable of leaving with the army. His ship, the
Violet, sank shortly after sailing and it is unclear if Stephen was injured in the wreck or if he had not been aboard because of an illness. In this way he avoided the controversial
siege of Zara in November. In March 1203 he decided not to rejoin the main army and went to southern Italy with Rotrou of Montfort and Yves of La Jaille. From there they sailed directly to the
Holy Land, possibly in the same flotilla or ship as
Simon de Montfort. ==Baron in Greece==