The colonization of the Americas took place in the mid-sixteenth century. It was, however, not due to the superior military strength of the Spanish conquerors. The most powerful weapon of the Spanish conquerors was not a conventional military weapon at all but it was primarily due to the global transfer of disease that helped in the colonization of the Americas. The Spaniards carried on their person, the germs such as those of smallpox into the Americas. The local inhabitants had no immunity against these diseases due to their long isolation.

It resulted in – spread of these diseases in the continent. Smallpox in particular killed and decimated many communities and paved the way for conquest and colonization of the Americas. It was not a Warfare. John Winthorp, the first governor of the Massachusetts Bay colony in New England, wrote in May 1634 that smallpox signaled, God’s blessing for the colonists ‘…. the natives … were near all dead of smallpox, so as the Lord had cleared our title to what we possess.’ Thus it can be said that the guns could be bought or captured and turned against the invaders but not diseases such as smallpox to which the conquerors were mostly immune.