This event has been celebrated on the first Sunday of August since 1961 and it was declared an International Festival of Tourist Interest in 2002. It marks the Norman incursions that took place in Galicia in the 12th century, as they came looking for treasures from Compostela and had confrontations with the locals. People gather on the shores and the bridge where the estuary of Arousa merges with the Ulla River. Over the course of the morning the town is filled with thousands of tourists who come to witness the arrival of a Viking longship, just like it happened about a thousand years ago. The ruins of the medieval defensive towers Torres del Oeste become the target of about thirty northern barbarians with horned helmets, who disembark yelling out their most ferocious battle cries. The armed battle for the defence of the towers is the focus at noon, and the festivities continue for the rest of the day with cultural events, folklore music and dances, a medieval market, mussel and red wine tastings, and rural meals. On this day the streets and promenade of Catoira are full of Vikings and visitors enjoying the festival.