His long and active career, in which he lost an eye, an arm, a leg and an ear, earned him international notoriety as an heroic, unbreakable soldier.

Of undistinguished birth, he also stood out for being an unusual example of a common man rising from footsoldier to maestre de campo for merit alone.

By 1547 he was part of Pedro de Gamboa's Spanish mercenary force commanding a unit as sergeant or captain at the Battle of Pinkie, as ally of the English in their war with Scotland known as the Rough Wooing.

During the three-hour duel, Romero lost his sword and lance and had his horse killed under him, but he managed to force Moura to dismount and wrestled him to the ground, where he subdued him with his dagger.

Romero fought in the Siege of Mons (1572), where he nearly succeeded in killing William the Silent in a daring raid against the Dutch camp.