Under the organization of the Navarrese Jaime del Burgo, and with the collaboration of the Carlism of Ondarroa, the first Biscayan third of Reques, the Third of Our Lady of Begoña, is organized.
Although the majority of Ondarroa's requeté will embark on the "Baleares", where many of them will meet their deaths. The Tercio is organized exclusively with Biscayns, passing command in June 1937 at the hands of the Army Commander Ricardo Uhagón Ceballos, a native of Bilbao with deep liberal roots.
His baptism of fire occurs in the breaking of the "Iron Belt" and in the taking of Santo Domingo for the entry into Bilbao. Its first advance was on Guernica, participating in its occupation, later passing to Morga as its base for the breaking of the "Belt", and from there to the subsequent taking of the position of Santo Domingo, key of Artxanda and Bilbao gate on 14 of June.
The northern campaign was carried out by the Tercio de Nuestra Señora de Begoña, first in the 5th Brigade of Navarra under the command of Colonel Juan Bautista Sánchez González, later he would be framed in the 61st Division, but he was added to the 1st Division for a time de Navarra under the command of D. Rafael García-Valiño y Marcén, the War would finally end in the 58th Division.
In the Santander campaign he took part in the occupation of Guriezo and Ampuero. From Riaño and within the 3rd brigade, he advanced towards the port of Tarna, intervening in the fighting at Peña del Castillo and the Grande de las Tablas position.
Already framed in the 61st Division under the command of Coronal D. Agustín Muñoz Grandes, the Tercio moves to Clares (Guadalajara) and later and due to the government offensive on Teruel the Division is sent to the front of Teruel and is positioned in La Muela, on the Albarracín road, next to San Blas.
In the relay of the Tercio de Nuestra Señora de Valvanera in the famous Cota 1062 "La Guea" south of La Muela de Teruel, the Tercio battles their weapons in the most intense and therefore bloody combats of their military history.
On March 16, the Tercio left for Huesca where it would carry out a campaign of rapid advance to the Cinca river and until it reached the Noguera-Ribargorzana river, occupying the towns of Fonz, Azanuy and Peralta de la Sal. The Tercio changed its Division and When he was placed in the 152nd Moroccan Division under the command of Ricardo Rada Peral, he was sent to the Guadalajara Front, specifically in Alcolea del Pinar and from there to Cortes de Tajuña where he would take positions, but would not enter into combat.
The Maestrazgo campaign is carried out by the Tercio from April 17 and from Santa Barbara passing through Morella to camp in Forcal and advance on the Cinctores line, Portell de Morella, Iglesuela del Cid, Villafranca del Cid and Mosqueruela, where the Tercio his mission was to take the position "Barragán" near Cantavieja where the enemy defended strongly, a position that the Tercio failed to take. The next actions were on the Milano hill at the "Silverio" position.
Again, the Tercio changes its Division, ceasing its addition to the 1st of Navarra and returns to the 61st Division, which will be part of the Galician Army Corps from September. The Tercio fights bravely in the Sierra de Espadan like his brothers del Lacar and Montejurra and settles next to the town of Sueras.
These Tercios would have to continue fighting from the Grao de Castellón towards the South, crossing Moncofar, Alamenara until reaching the last military objective in Torres-Torres, passing to rest in Aldaya. On June 19 he moved to Bilbao to participate in the commemorative parade of the taking of the City by the National troops.
Contents of the Journal,