Battle of the Trench enemy in the open (which led to victory at Badr), and waiting for them inside the city (a lesson learnt from the defeat at Uhud) were both suggested. Ultimately, the outnumbered Muslims opted to engage in a defensive battle by digging deep trenches to act as a barrier along the northern front. The tactic of a defensive trench was introduced by Salman the Persian. Every capable Muslim in Medina including Muhammad contributed to digging the massive trench in six days. The ditch was dug on the northern side only, as the rest of Medina was surrounded by rocky mountains and
Army of the North victory. The battle was favorable to Balcarce even though he again had numerical inferiority (800 royalist against 600 rebels, and in Cotagaita 2,000 royalists against 1,100 rebels). Balcarce earned the rank of brigadier, and the confidence to advance towards the Desaguadero River, border of the viceroyalty in colonial times. Due to internal disagreements Castelli had to dismiss Güemes and his gaucho soldiers. The royalist defenses were left in charge of general José Manuel de Goyeneche, who met with Castelli and signed an armistice to last for forty days from 16 May. The army moved from the encampment at La Laja,