In the last week of July , many of the town 's 16,000 inhabitants parade and fight in richly costumed companies los piratas , los tuareg , and los moros del Rif among them re-enacting the defeat in 1538 of the Algerian pirate Zala Arraez , a Mediterranean scourge who started it all by sacking the castle in a daring dawn raid .
The raid was conducted by a force of fifty soldiers .