outposts and to disrupt the transport of rice to Cholon, the main commercial hub of southern Vietnam. The first major attack against the French administration in the area targeted the Gò Công district office on June 22, 1861. At 05:00, 600 rebels under the command of Do Dinh Thoai stormed the military post in the town, engaging the French troops in hand-to-hand combat with lances, bayonets, knives and bamboo sticks. The French were surprised by the attack, losing one soldier and having 100 wounded. By the time reinforcements and naval cover had arrived from Mỹ Tho, Định's men had fled. Thoai—who had been the district chief until the French invasion—was among the 14 killed. On September 27, the guerrillas assassinated the French-installed chief of Gò Công, displaying his severed head in the town market. The chief's servant, who was an informant for Định, aided this operation. The killing had the effect of intimidating the chief's designated successor into submitting to the rebels and ceasing his service for the French. In November 1861, Định's men went into the town of Mỹ Tho to recruit militants and collect food supplies. During this time, they attacked and burned pro-French villages and their leaders. Định's Gò Công insurgents attempted to stop rice from being shipped to Cholon by attacking the French lorchas and apprehending the trading vessels on the local waterways. A French report in November 1861 noted that shipping had been severely disrupted and restricted, despite high levels of French naval protection. The most notable of the seaborne attacks was the burning of the lorcha L'Espérance on Nhat Tao Canal on December 10, 1861. Around 150 guerrillas commanded by Trực ambushed the vessel, killing some of the crew before burning and sinking the boat. The attack buoyed Vietnamese morale and instilled the belief that they could fight against French naval forces. The sinking earned the specific praise of Emperor Tự Đức, who described the incident as "most outstanding". Continued guerrilla campaign However, the overall Vietnamese military performance was not as successful as Định's guerrilla activities. On June 5, 1862, Định broke with the Nguyễn army after the court's plenipotentiary Phan Thanh Giản and another official, Lam Duy Hiep, signed the Treaty of Saigon. This agreement ceded the three southern provinces of Gia Định, Định Tường and Biên Hòa to France; they became the colony of Cochinchina. The treaty was accompanied by financial payments