the answer to this question is that Spain was able to acquire vast territories in the New world, in south and northern America.
The early conquest of the new world followed closely the emergence of a united Spain following the unification of Castile and Aragon. Princess Isabella of Castile married Ferdinand of Aragon was able to finance exploration into the new world earlier that any other powers,therefore laying ground for early settlement of the Spanish in the region. One of the main motivating factor that Historian attests to was spreading the catholic faith.