Gruppe Thoma formed part of Gruppe Imker, the ground formations of the German Condor Legion, who fought on the side of Franco's Nationalists.[42] Between July and October, a rapid Nationalist advance from Seville to Toledo placed them in position to take the Spanish capital, Madrid.[43] The Nationalist advance and the fall of the town of Illescas to Nationalist armies on 18 October 1936 caused the government of the Popular Front's Second Republic, including President Manuel Azaña, to flee to Barcelona and Valencia.[44] In an attempt to stem the Nationalist tide and gain crucial time for Madrid's defence, Soviet armor was deployed south of the city under the command of Colonel Krivoshein before the end of October.[45] At this time, several T-26 tanks under the command of Captain Paul Arman were thrown into a Republican counterattack directed towards the town of Torrejon de Velasco in an attempt to cut off the Nationalist advance north.