The Boston Tea Party was an event in which patriots in the American colony of Massachusetts dressed as Mohawk Indians and threw 342 chests of tea that belonged to the British East India Company into Boston Harbor. 

The Boston Tea Party took place on December 16th, 1773. 

The Boston Tea Party occurred because the colonists were upset about being taxed on tea without being allowed representation in the English government (taxation without representation). 

The taxes on tea were originally created in the Townshend Acts, which were passed by parliament in 1767. The Townshend Acts imposed taxes on various goods including tea that were imported into the American colonies from Great Britain.  The Townshend Acts were repealed in 1770 due to significant protests and noncompliance from the colonists. However, Parliament left the duty on tea. 

In 1773, Parliament also passed the Tea Act, which created a monopoly for the British East India Company in the tea market and made it impossible for the colonists to avoid the hefty tea taxes by getting tea from non-British sources. This led to a lot of anger and frustration by the colonists who did not enjoy having taxes imposed on them that they had no say over.