What advantages allowed Spain and Portugal to expand overseas first?

As Spain expanded
into the Americas and Portugal moved into West Africa, Brazil and India, their military strength
played an important role in their expansion.  Military innovations such as firearms and well
built and militarized ships gave these European countries an advantage over the indigenous
people of their acquired colonies.  Monetary strength from both financial endowments and trade
kept the colonies financially strong.  Both Spain and Portugal enslaved many of the original
occupants of their conquests.  Although slavery is considered immoral, at the time it helped
secure these counties hold on their expansions by increasing the labor force.   Spain especially
benefited from the use of slaves to mine silver which greatly supported their economy in the
16th century.  And finally, Spain and Portugal were successful in their expansions because they
really didnt have any additional European competition.  Political weakness plagued Italy,
England wasnt interested in the Southern Hemisphere, and France was preoccupied with other
matters.