The Muslim forces march on Uclés, which offers no resistance and is captured on May 27.

The Almoravids now spread out, sacking other Christian settlements in the valley of the Tagus, while the inhabitants flee.

The garrison of Uclés meanwhile takes refuge in the alcázar.

The Historia Compostelana says that it was the heir, Sancho, who initiated a counterattack.

This is plausible in light of the fact he had already been granted the rule of Toledo by his father, who is in the north of the kingdom at the time of the Almoravid offensive.

Sancho had probably moved south with a sizable army in April in preparation for a summer of campaigning.

His army included eight Leonese counts and Castilian magnates (los ochos condes of legend), who, with their heavy cavalry retinues, probably count for a fifth of the total heavy cavalry resources of the crown.

Including Sancho’s personal guard, the number of Christian troops is probably about four hundred knights and an equal number of squires and grooms: about twelve hundred men total.

A contingent of townsmen from Calatañazor, Alcalá, and Toledo, led by their alcaldes, numbering probably seven hundred and fifty, mostly infantry but some light cavalry, had joined the main force before the battle.

Including three hundred or so men involved in the baggage train, Bernard Reilly estimates a total number of twenty-three hundred Christian troops, while the Arabic sources mention three thousand Christian heads piled in front of Uclés to terrorize the citizens.

It has been suggested that the Muslims forces would have had to be far superior in numbers in order to execute the successful enveloping tactic they did.