 To further strengthen the Allied ranks , a force of Spanish irregulars under General Antonio <unk> de los Ríos had been ordered to come down from the Ronda mountains by 23 February and join the main Anglo @-@ Portuguese and Spanish force . Unaware of the delays in sailing , <unk> had advanced as far as Medina @-@ Sidonia in search of the Allied army ; unsupported , and embroiled in skirmishes with Victor 's right flank , he returned to the mountains . General Cassagne , Victor 's flank commander , informed the Marshal of the developing threat . Victor responded by sending three infantry battalions and a cavalry regiment to reinforce Cassagne , and ordering the fortification of Medina @-@ Sidonia . 
