He did not take the field until the Carlist cause appeared to be at a very low ebb, and until he had received a commission from Don Carlos as Commander-in-Chief in Navarre. He escaped Pamplona on the night of 29 October 1833 and took the command next day in the Araquil Valley. At that time the Carlist forces comprised no more than a few hundred ill-armed and dispirited "guerrilleros"; in a few months Zumalacárregui had organized them into a regular army. The difficulty he found in obtaining supplies was enormous, for the coast towns and notably Bilbao supported the "Cristino" (liberal) cause. It was mainly by seizing equipment from the government troops that he armed his forces. He gradually obtained full possession of the Southern Basque Country, outside of the fortresses, which he had not the means to besiege. He organized the forces known as "aduaneros" and the "Guías de Navarra". His chief bodyguard, and later biographer, was Charles Frederick Henningsen. Whether as a guerrilla leader, or as a general conducting regular war in the mountains, he proved unconquerable. He won the battles of Alsasua, Alegría de Álava, and Venta de Echavarri, for example, by employing guerrilla tactics. By July 1834 he had made it safe for Don Carlos to join his headquarters. Zumalacárregui was by then strongly envied by the courtiers that surrounded the pretender, as well as by other military officers. Besides, Don Carlos was a somewhat naïve and easily suggestible man, and Zumalacárregui had therefore to drag behind him the whole weight of the distrust and intrigues of the court. Yet by the beginning of June 1835 he had made the Carlist cause triumphant to the north of the Ebro, and had formed an army of more than 30,000 men, of much better quality than the constitutional forces. He won the battle of Artaza (20–22 April 1835). If Zumalacárregui had been allowed to follow his own plans, which were to concentrate his forces and march on Madrid, firstly seizing Logroño (La Rioja, Castile), he might well have put Don Carlos in possession of the capital. But the court was eager to obtain command of a seaport, because they thought this will facilitate the official recognition of Don Carlos as the legitimate heir to the Spanish Throne by other European courts.