A memorable event in the Spanish Civil War, the siege lasted from July 19, 1936, until October 16, 1936. The town garrison under the command of Colonel Antonio Aranda Mata declared for the rising and held out until relieved by a Nationalist Army.
The Nationalists did not consider Oviedo, capital of the province of Asturias as a likely place for a successful revolt and indeed initially it was considered lost for the rising. The city was the center of the Asturian October Revolution (1934) and was a seething center of revolutionary activity since the election of the Popular Front Government earlier in the year.
Aranda was reputed to be a freemason and a republican and got along well with the local republican officials. In addition the Falange distrusted him. Aranda made noises that he would be loyal to the Republic when the rising started on July 17. He convinced the civil governor and the union leaders that all was calm. So convinced were the authorities that 4,000 miners left by train for other parts of Asturias and Spain to fight the rising. Aranda called in the Civil Guard and Assault Guard personnel from all Asturias to concentrate at Oviedo. Aranda had gained the reputation in Africa of being a top strategist, and after the miners left, he declared for the rising on July 19. The Falange, Civil Guard and Assault Guard rallied to his side.Aranda easily took over Oviedo as the left panicked. The rest of Asturias was hostile to him, however. Between the two large proletarian zones, east and west of Oviedo, Aranda was landlocked and surrounded in the town.
Aranda realized from the beginning that he would have to hold the town and had made intelligent and extensive preparations. He had carefully studied the defense of the place and having at first much equipment from the barracks in Oviedo, he sited over 100 Hotchkiss machine guns in five strategic nuclei in about a nine mile perimeter around the town. The town was not that easy to defend as it was surrounded on all sides by heights, but Aranda took that into consideration and held the heights to lay down curtains of fire. Aranda's tactics were novel for the time as it considered that a town as vulnerable as Oviedo could be held by fire-power alone. Aranda's plan did have one serious hole as he only had about 3,000 defenders counting regular forces, guards and volunteers. That meant he could not occupy all the heights and this gave the attackers one advantage. The Republican Government in Madrid had reinforced the garrison at Oviedo after the 1934 revolution and had sent large amounts of guns and ammunition for storage there. In addition to the large number of machine guns, Aranda had over a million rounds of ammunition. During the relatively quiet time during August, Aranda improved his position by constant offensive thrusts that kept the besiegers in doubt.
Since the siege had no regular Republican ground forces the "Republican forces" were almost solely militia from the Popular Front parties and the allied Anarchists, and they began besieging Oviedo on July 20, but at the same time had to conduct the Siege of Gijón also in Asturias. The Nationalists at Gijón's Simancas Barracks held out until August 16, 1936. Thereafter the Popular Front forces could start to concentrate on Oviedo. The final Nationalist Resistance ended in Gijón on August 21 and the Gijón militia could join the siege of Oviedo. The fact was, however, that about two hundred defenders had tied down the entire militia of that area for a month. Valuable time had been gained by the Nationalists and lost by the Republicans.
After the end of the conflict in Gijón the Popular Front forces were able to say close siege to Oviedo. Most of the attacking militia were miners from the many Asturian mines. The besieging force had several problems. As noted, it lacked professionalism with few if any trained military men as almost all such troops, including a majority of the Assault Guards, had rallied to the rising. In addition a Nationalist Relief force was on the way from Galicia and the siege in Gijón had drained away forces needed to oppose that advance. The relief force had made substantial progress towards Oviedo. The Popular Front forces had little proper equipment to conduct a siege with the exception of dynamite. Last and not least was the terrain. With the seizure of the heights around Oviedo, Aranda assured that Oviedo was admirably suited for defense.
Two union members, Otero, a socialist miner, and Higinio Carrocera, an anarchist steelworker, assumed leadership of the siege. The attackers had cut off the water supply from the very first. The defenders however, made the city reservoir one of the defended strong points, and with rationing were able to continue. Water could not be used for sanitation, however. Oviedo was a warehouse center for all Asturias, and so the garrison and populace had plenty of food at first. Little fighting occurred until September 4, when the attackers launched a ferocious aerial and artillery bombardment. 1,500 bombs were dropped on the town cutting the gas, light and telephone systems and blacking out the town. Four days later, supported by an armored plated steam roller, the attackers tried to take the most remote outpost. The defenders raised artillery pieces on sandbags to act as anti-aircraft guns. After a twelve hour battle, the attackers were driven off.
The heavy shelling was killing large number of civilians, and the water shortage was killing more due to the lack of water for sanitation. As is the case in many such occasions, the shelling and bombing were counter-productive as far as acts of terror were concerned. Many people who were sympathetic to the Popular Front joined the forces defending Oviedo because a family member was killed or injured by the attackers' explosives. The danger of a rising against the defenders quickly receded as the attackers intensified the bombardment and caused more civilian casualties. One advantage to the defenders was that a large portion of the population was politically neutral.
The attackers tightened the siege further as September wore on. The lack of water for sanitation started a typhus epidemic that had a high fatality among the old and very young. As an aside, Oviedo was remarkable during the siege that the defenders executed none of the political prisoners whom they held in captivity. That might have been unique in Spain at this time on both sides of the war.
October 4, was the day before the second anniversary of the beginning of the Asturias Revolution of 1934, and the Popular Front militias made an all out attack on that day. The attackers were in a hurry since units from the tough Army of Africa had reinforced the Nationalist relief column from Galicia. Although the Popular Front had held up that relief column for two weeks, it was only fifteen miles from Oviedo. Aranda had lost half his defenders and the attackers rolled over one of his defense points and he lost part of the high ground around the town. The fighting raged for a week and one by one, the defender's strong points fell to the attackers. Aranda abandoned what was left of the perimeter and pulled his survivors back into the town. He had used 90% of his ammunition by this time. The defenders ran out of machine gun ammunition and the fighting reverted to hand to hand combat. The attackers fought from house to house by cutting holes in the walls joining the houses. The defenders were almost out of ammunition when some Nationalist airmen managed to drop 30,000 rounds to them.
Aranda had only 500 defenders left and he pulled them into the center of the town for a last stand. The Popular Front militia captured the last power plant and the interior of the town was blacked out. Aranda retreated into the barracks in the middle of the defense, and with a radio powered by a car battery, he exhorted the defenders to fight like Spaniards to the end. He sent a message to the relief column from Galicia to state that his troops were out of ammunition, but they would fight to the last. The Popular Front militias had suffered enormous losses themselves, at least 5,000. They were low on ammunition and were making slow progress. Each house had to be destroyed to end the resistance, and the defenders refused to surrender and died to the last man. Then with the defenders at almost their last gasp, the Galician relief column arrived and the Popular Front militia, almost out of ammunition, halted. It was October 16, 1936.
The Nationalists won a narrow corridor into the city and held it until the end of the War in the North a year later. The Popular Front militias abandoned the town and retreated to their positions occupied at the start of the siege. Oviedo, however, was no longer in danger. Aranda would continue to serve the Nationalist cause including the Battle of Teruel and other conflicts during the war.