04 November 1512,
On the outskirts of the walls of Pamplona a struggle began between the Navarro army and the Castilian occupant. The Navarros legitimists had the city surrounded a few days earlier. The Duke of Alba sent a group outside the walls to fight Juan de Albret, but in the meantime, fearing that the Non-Citizens would rise in favor of his king, the Duke of Alba established a huge repression. The following day, the Navarros’ legitimists, together with the French allies, decided to attack the walls of Pamplona in their attempt to recover the city.
Source:
Joseba Asiron and Martín Altzueta, 50 key dates of the conquest of Navarra (1512-1525) (Txalaparta).