When he was halfway across the Aztecs turned, reinforcements arrived from the city, swarms of canoes attacked the Spaniards in flank; and it was only after desperate fighting, and some loss, that they regained the mainland.
Having accomplished their object, the force returned to Tezcuco, greatly harassed on the march by the enemy.

Other expeditions were undertaken.

During these events the work of putting together the vessels was continued and, to the great satisfaction of the Spaniards, news reached them from the coast of the arrival of three ships, with reinforcements: two hundred men, seventy or eighty horses, arms, and ammunition.
When these reached Tezcuco, Cortez felt confident that he should now be able to overcome all opposition.

On the fifth of April he again started on an expedition.

Passing through some deep gorges, he attempted to carry a mountain fortress; but was repulsed, with loss, from the volleys of stones and rocks rolled down upon the assailants.
After several other battles they neared Xochimilco, one of the richest of the Aztec towns.