Which event cause the boston masscure to occur

The Stamp Act And Other Taxes That lead the colonist to be angry at the British throwing stuff at them like snowballs and rocks which lead to britsh firing at them killing five of them

The tension produced by the military occupation of Boston increased after the firing of a group of soldiers against a group of nobles who protested against the increase of the rates on the part of England.

The answer is: The protest of a group of nobles against the increase in rates.