He participated in the Pêro Coelho expedition to Ceará in 1603 and ended up becoming, years later (1612),[1] the virtual founder of that colony.

[2] There he built, on the river Ceará, a fort and a chapel, with the help of the Indians that he brought from Rio Grande do Norte.

The next year, now a captain, he returned to Maranhão, together with reinforcements of 900 men, which made possible the definitive expulsion of the French and the capture of the city of São Luís.

In 1616 he was captured on the high seas by a French Corsair, after a violent battle that left him seriously wounded with a cut on the face and the loss of a hand.

Nevertheless, in 1645, Martim Soares Moreno took part in the clandestine movement that ended with the expulsion of the Dutch from Brazilian territory.