Philip II, as everyone knows, was an armchair strategist; he lacked the physical stamina of a military man, and the nearest he came to seeing a field of battle was his visit to St. Quentin (1557) after his troops had gained him a great victory there. Charles V was wise enough not to push his son beyond his limits; he never made him participate in one of his many wars. Yet a legend of relatively recent origin now sees Philip take part, at the age of fifteen, in the Spanish triumph (1542) at Perpignan.
The facts of this event may be summed up as follows: In the summer of 1542, after not quite four years of the ten-year truce between Charles V and Francis I had passed, French armies under the Dauphin (the later Henri II) set out in June toward Narbonne, aiming to advance on the (then) Spanish county of Rosellón (Roussillon), laying siege to Perpignan in the latter part of August. The Duke of Alba, anticipating their approach, had improved Perpignan's fortifications in good time and lined up an overflow of Spanish armies ready to meet the attackers.