The renowned Espoz Mina presented his irrevocable resignation in April 1835, leaving the military command in the hands of General Valdés, who was also Minister of War. Although previously defeated by Zumalacárregui, Valdés now had more troops.
As soon as he reached Euskal Herria, Valdés took 20,000 soldiers and went to take the refuge that Zumalacárregui most loved: the Valley of Las Améscoas.
Zumalacárregui had just 5,000 men in his defence, but the narrow valley made it difficult for so many troops to pass. On the 21st of April, the Liberals entered Améscoa and took the town of Eulate while Zumalacárregui retreated to San Martín.
After burning the Carlist gunpowder factory in Eulate, the Liberals then headed to Urbasa by the ports of Eulate and Aranarache. The 20,000 Liberals spent an uncomfortable night marked by Carlist guerrilla shots near the Venta de Urbasa, while the Carlists had split up and were resting in different villages in the Valley of Las Améscoas.
The day after, the Liberals began their descent of the port of Artaza with the idea of taking refuge in Estella. But the Carlists were waiting for them. After a tough combat, the Liberal used their numerical superiority to clear their way through and escape towards Estella, with the Carlists hot on their heels. The journey from Urbasa to Estella turned out to be very difficult for the Liberals, as they were too many for the narrow paths they had to cross. Some arrived in Estella at nightfall, while others took refuge in Abárzuza. In the confusion brought by nightfall, the Liberals began shooting at each other, causing 50 casualties in the lines of Valdés, with a further 200 wounded and 250 taken prisoner by the Carlists.