During the 1936-1939 war, the possession of Peña Lemona was fiercely disputed by both sides. Its proximity to the Bilbao Belt -4 Kms. - and to the Biscayan capital -13 Kms. in a straight line- as well as its preeminent situation from which the roads from Amorebieta and Lemona to Galdakao were dominated, gave the crag an extraordinary strategic value that did not go unnoticed by defenders or attackers. After many years we have been lucky enough to obtain the manuscript that reads as follows: "Year 1937. Operations Diary. 1st Group of the 2nd Navarre Brigade". Chief of the attacking forces: Lt. Colonel D. Jesús Esparza Arteche. On pages 10 and 11 is the history of the occupation of the Peña de Lemona which we transcribe:
"Day May 29, 1937. Today, the occupation of the town of Amorebieta, elevation 216 and Peña de Lemona was carried out by the forces of this Half Brigade".
On the 27th, the Simón Bolibar Battalion and the Asturian battalions numbers 225 and 230 occupied the Peñas de Lemona.
"On the 29th at 5:00 p.m., the advance towards the Peña de Lemona was undertaken again, being Arapiles with two companies of Falange who proceeded to the occupation, leaving the other two with Commander D. Emilio González, to protect the right flank and the term of Ntra. La Peña was occupied by assault at 8:30 p.m. Seven militiamen passed through".
The assault was preceded by an intense artillery and aerial preparation truly impressive and was facilitated by the defection of the battalion n.° 230. The night of the 30th there was a counterattack without result. On May 31 there was a new counterattack by the Bolibar battalion which, with its commander Echegoyen at the head, managed to break through several points of the national defenses. After an hour of combat the Bolibar was forced to retreat due to the inactivity of the Asturian battalions No. 225 and 230. New attacks on the 1st and 2nd without result.
"On the 3rd, around 8:30 in the morning, the Peña de Lemona was attacked, after intense artillery preparation, protected by caterpillars approaching from the right flank 200 meters from the position. The Tercio de San Ignacio that garrisoned it abandons it, and is counterattacked at 1:15 am by three companies of Arapiles and two of Falange protected by the Hochtkiss machine guns of Arapiles, remaining in reserve in the Pinar Alto a Battalion belonging to the 2nd Half Brigade, recently arrived. With the protection of the 10.5 Group (artillery) of the Brigade, this attack was carried out, which could not progress beyond the beginning of the burnt hill that constitutes the position due to the deadly fire of the enemy machine guns that caused many casualties to the assaulting companies in a very short time. In order to reinforce our lines, two other battalions arrived under the command of Lt. Colonel Castra, leaving these two in reserve and continuing the first one to arrive at Pinar Alto, which became our advanced line".
After Commander Gorritxu was relieved of his command, the IV Basque Brigade, whose command had been entrusted to Commander Cristobal Errandonea with the Rosa de Luxemburgo, Dragones and Amuategui battalions, returned to attack Peña Lemona. Taking advantage of the fact that the rain and wind made it difficult for the aviation to act, the 4th, 22nd and 35th battalions, supported by two small tanks whose presence greatly surprised the defenders, took it early in the morning after forcing the Nationalists to vacate it with many losses. Franco's troops counterattacked several times, being repulsed.
"On the afternoon of the 5th, after intense artillery preparation, which began at 17:45, the Peña de Lemona was occupied again. The attack began at 7 p.m., carried out by 160 men of the San Ignacio Tercio, the 2nd Company of Ntra. Sra. del Camino and the 2nd and 4th Companies of the Arapiles in second echelon, protected by machine guns of the same Corps."
The Simón Bolibar Battalion was destroyed in these days and was withdrawn to the rear. According to the rebels' Operations Diary, their casualties were on the 29th seventy-eight, on the 3rd two hundred and fifty-three, on the 5th five hundred and seventy-seven, for a total of nine hundred and thirty-five. It can be calculated that the total the two sides would pass one thousand six hundred in a field like a soccer field. In the Diary are expressed the names and surnames of the chiefs and officers who were killed and wounded with a total of twenty-six, of their own troops. An extraordinary number in so few hours of combat, justified by the urgent need to occupy La Peña and by the concentrated focus of operations. On June 11, the magnificent painter and multifaceted artist Nicolás de Lecuona died at the age of 24, in the front of Frúniz.
Translated with DeepL.com (free version)