[2][3] In 1515, Manuel I of Portugal sent an armada consisting of 8,000 men and 200 ships,[4] led by D. António de Noronha [pt], Count of Linhares[a],[5] with a task of capturing and building a fort in Mehdya,[6] naming it Sao João da Mamora.

[7][8] Arriving there, the low tide and shifting sandbars left the Portuguese ships stranded.

[10] The Moroccan counter-attack came in July when the sultan's younger brother and the grand vizier Moulay Nasr who besieged the Portuguese from the north, the sultan came and besieged them from the south bank of Sebou River[11] the sultan concentrated his artillery on the Portuguese ships while his brother invested on the fort, the sultan watched his artillery hit one of the ships with an incredible shot,[12] within an hour the whole nature of the siege changed, the escape route was blocked, no longer being threatened by Portuguese cannon ships, the sultan ordered twelve light artillery to move straight to the river shore, the Moroccan pressed the Portuguese with Explosive grenades close to the Portuguese lines,[13] the Moroccans stop firing and the Portuguese began to dismantle the fort and start escaping in small boats, However seeing the Portuguese fleeing, the sultan gave signal and attacked the Portuguese, by the end of afternoon the water of Sebou turned red as Leo Africanus who witnessed the siege said:[14] For three days the sea spouted waves of blood.Portuguese casualties were heavy, 4,000 were killed and 100 ships were lost.

[18] It was a decisive victory for Wattasids, it shattered Manuel's and Portuguese hopes to conquer entire Morocco.

[19][20] Seeing the Portuguese pride was shattered, the captains of the forts ordered raids after raids into the interior of Morocco to prove the Portuguese military had not been broken, the governor of Safi Nuno Fernandes de Ataide launched a raid into Oulad Umran tribe however he was defeated and killed and only 100 men escaped.