The process of Vietnam's colonization began in September 1858 when a Franco-Spanish force landed at Da Nang in central Vietnam and attempted to proceed to the Vietnamese imperial capital of Huế. After meeting stiff resistance, they sailed down to the less-defended south, and quickly captured the Citadel of Saigon in February 1859, before looting and razing it. The leaderless and defeated imperial troops fled in disarray. The French then withdrew, but returned in 1861 in a more serious attempt to claim and occupy Vietnamese territory. In February of that year, the French attacked the citadel of
Ky Hoa, seizing the fort after two days, along with a large quantity of small arms, artillery and food. Trương Định, a local partisan leader who fought at Ky Hoa, incorporated soldiers from the defeated imperial army into his ranks, as its commander had committed suicide.
In 1861, the resistance leaders in the Gò Công area delegated Dinh to travel to Biên Hòa to seek permission from imperial military commissioner Nguyen Ba Nghi to "turn around the situation". Dinh's men were armed with bladed spears, fire lances, knives, sabers, bamboo sticks and swords, trained and on call as necessary. Truc was one of the partisan leaders who assisted Dinh. Truc's partisan band was based at Tân An The French were aware of his activities, with an intelligence dossier calling him a "likable and intelligent man".