The major event that occurred in Boston in 1773 as a protest against British taxation is the Boston Tea Party. This act of defiance was organized by American colonists who were frustrated with the Tea Act, which granted the British East India Company a monopoly on tea sales in the colonies. Disguised as Native Americans, colonists boarded British ships and dumped 342 chests of tea into Boston Harbor as a demonstration against taxation without representation. This incident escalated tensions between Britain and the colonies, leading to the implementation of punitive measures by the British government and ultimately contributing to the onset of the American Revolution.