The Portuguese and Spanish conquest and colonisation of America was decisively under way by the mid-sixteenth century.

(i)In fact, the most powerful weapon of the Spanish conquerors was not a conventional military weapon at all. It was the germs such as those of smallpox that they carried on their person.

(ii)Because of their long isolation, America’s original inhabitants had no immunity against these diseases that came from Europe.

(iii)Smallpox in particular proved a deadly killer.Once introduced, it spread deep into the continent, ahead even of any Europeans reaching there

(iv)It killed and decimated whole communities, paving the way for conquest. 

(v)Guns could be bought or captured and turned against the invaders. But not diseases such as smallpox to which the conquerors were mostly immune.