Biên Hòa to seek permission from Imperial Military Commissioner Nguyen Ba Nghi to "turn around the situation". Appointed to the rank of lieutenant colonel, Định began to stockpile foodstuffs, manufacture weapons, and recruit forces from the populace with the help of officers from the imperial army. His forces grew to around 6,000 men by June 1861. The French began to report that junks from Singapore and Hong Kong had arrived in Gò Công with shipments of European-made weapons. Định's forces began inflicting substantial damage on the European troops, largely because of their intimate knowledge of the terrain, skill in hit-and-run guerrilla tactics, and support from the local villagers. Định's men focused on chasing French soldiers around the countryside and attacking military installations that were left undefended as a consequence of their guerrilla pursuit. Learning of Định's role in support of the Nguyễn dynasty's call for popular resistance, Tự Đức promoted him to the rank of lieutenant colonel for the Gia Định region. Later in 1861, the imperial regulars were defeated at Biên Hòa, and the commanding Vietnamese officers were ordered by the royal authorities to meet Định at Tan Hoa to develop a plan for retaking Biên Hòa. As a result, the number of troops under Định's direct authority grew. Early in 1862, the Nguyễn court granted Định command of all the southern nghĩa quân (righteous soldiers), the term that Huế used for the partisans. Định continued to lead raids on enemy forces from his base in Gò Công. Friction developed between the regular army and Định's partisans as to whether to stage aggressive sorties from Tan Hoa, as was Định's strategy, or to bide their time and engage in military buildup. Định's nghĩa quân quickly earned the respect of the opposing French naval officers. Léopold Pallu de la Barrière, who defended the posts at Gò Công from Định's attacks, was surprised by their ferocity. Unaware of their nationalist feelings, de la Barrière had expected the Vietnamese to live submissively under any ruler that would allow them to sow their crops. He wrote: He went on to recognise the popular nature of the partisans' efforts, stating that the "centre of resistance was everywhere, infinitely subdivided"; he regarded every peasant as a centre of resistance. Notable attacks From the middle of 1861, Định's Gò Công guerrillas focused on three objectives: to disrupt the newly created French bureaucracy, to disrupt their military