Although the defeat of the Armada and the outbreak of the Eighty Years War in the Low Countries have colored perceptions of Philip II's reign as a failure, there were three areas in which he managed to put Spain on a very solid footing.

• The Battle of Lepanto and the Holy League managed to check to expansion of Ottoman naval power at the Battle of Lepanto. Although the battle was not as decisive as the Spain's popular celebration of it suggested, the battle denuded the Ottoman fleet of skilled personnel and put them at a disadvantage in the Mediterranean for some years. Although there were bursts of Ottoman activity and expansion, the Mediterranean became something of a quiet zone for Spanish interests.

• This quiet zone also relates to how Philip II was able to translate Spanish military dominance over Italy into something of a permanent political domination of the peninsula. Naples and Milan became direct dependencies of the Spanish crown and other Italian kingdoms became client states of Spain. Although this was not terribly popular among some Italian elites, Italy became a source of financing, men (especially generals), and material for Spanish armed forces operating in the Low Countries. The Habsburg preeminence in Italy would last for roughly 50 years until the quagmires of the 1640s.

• Finally, the Alba's conquest of Portugal was an example of how to invade a very difficult region. Philip II and his ministers managed to sideline several pretenders to the Portuguese throne while Alba managed a successful invasion that accomplished its aims quickly after one battle, the Battle of Alcântara. Achieving such successes quickly and without recourse to long sieges was a rare feat for early modern armies and Philip II was able to very swiftly establish the Iberian Union because of them. Again, like Italy, this lasted until the crisis years of the 1640s.