The dispute between Guy and Raymond threatened the security of the Kingdom, as Guy planned to besiege Raymond's fief of Tiberias, which itself had allied with Saladin.
Balian of Ibelin, another of Raymond's supporters, instead suggested that Guy send an embassy to Raymond in
Tripoli, hoping the two could be reconciled before Guy made a foolish attack on Saladin's larger army. Reginald accompanied Balian,
Gerard of Ridefort (
Grand Master of the Knights Templar),
Roger de Moulins (
Grand Master of the Knights Hospitaller), and
Joscius, Archbishop of Tyre to Tripoli. On May 1, the Templars and Hospitallers were defeated by Saladin's son
al-Afdal at the
Battle of Cresson; Balian had stopped at his fief of
Nablus and Reginald had stopped at his castle at
Beaufort, and the two were not present for the fighting. Raymond heard news of the defeat, met the embassy at Tiberias, and accompanied them back to Jerusalem. The subsequent invasion of the Kingdom by Saladin was met by Guy, Raymond, and the crusader army at the
Battle of Hattin. The battle was a crushing defeat for the crusaders; Reginald was in the rearguard with Balian and
Joscelin III of Edessa, his late wife's brother, and escaped with them; according to later western chronicles of the
Third Crusade, they were cowards and trampled their own men in the rush, but more likely they were simply trying to break the Muslim encirclement of the crusader army. This did not work, and Reginald and Balian fled to
Tyre, where Reginald may have briefly taken command of the city after the departure of Raymond of Tripoli. The thirteenth century
Old French Continuation of William of Tyre, including the
Chronicle of Ernoul, claims that he was in the process of negotiating its surrender to Saladin when
Conrad of Montferrat arrived. Saladin had given Reginald banners to be hung from the city's towers, but Reginald was afraid of retaliation from the citizens if Saladin himself was not present. Conrad threw the banners away and expelled Reginald. However, this is questionable: the Arab chroniclers say nothing of this, and subsequently Reginald and Conrad were close allies. Reginald may have left Tyre for Beaufort (Sidon having also been captured in the aftermath of Hattin), just as Raymond III had left for Tripoli: the priority of such magnates being to defend their own territories. However, he was certainly back in Tyre in 1188, when he witnessed a charter for Conrad. In 1189, Reginald entered into negotiations with Saladin for the surrender of Beaufort. He offered to retire to
Damascus and convert to
Islam, but it was all a ruse: he was only wasting time in order to allow the defenses of the castle to be strengthened. Upon returning to the castle he ordered its guards to stand down in
Arabic, but in
French told them to continue their resistance. According to
The Old French Continuation of William of Tyre, Saladin tortured Reginald outside the castle until the garrison surrendered, although in reality it does not seem to have surrendered at this time; Reginald was imprisoned in Damascus, and the castle eventually fell on April 22, 1190, in return for his release. After his release, Reginald married
Helvis, the eldest daughter of
Balian of Ibelin and
Maria Comnena. He then played an influential role in the politics of the
Third Crusade. He supported the annulment of the marriage of
Humphrey IV of Toron and
Isabella of Jerusalem, so that Isabella could be married off to Conrad of Montferrat; the anonymous author of the
Itinerarium Peregrinorum et Gesta Regis Ricardi calls Reginald a member of a "council of consummate iniquity" (together with Balian of Ibelin and Maria Comnena and
Payen of Haifa) for supporting this act. His Arabic skills made him useful as a diplomat: he negotiated with Saladin on behalf of Conrad in 1191-92, and later helped negotiate peace between Richard and Saladin in 1192. Sidon was recovered from Saladin in 1197. ==Personal life==