 De Beauregard went to Siam in 1685, with the embassy of Chevalier de Chaumont.He was transferred to the garrison of Bangkok, under the command of Chevalier Claude de Forbin.In July 1686, when the fort was attacked by a band of pirates from Makassar, de Beauregard's belly was slit open with a dagger, but his commander de Forbin managed to replace the viscera and sew him up, making him the first recorded case of a Western-style surgical intervention in Thailand.