May 10, 1773 -- The Parliament of Great Britain passes the Tea Act.

W.D. Cooper. "Boston Tea Party.", The History of North America. London: E. Newbury, 1789. in book: The History of North America. London: E. Newberry, 1789. Engraving. Plate opposite p. 58. Rare Book and Special Collections Division, Library of Congress (Public Domian)

The Tea Act 1773 (13 Geo 3 c 44) was an Act of the Parliament of Great Britain. The principal objective was to reduce the massive amount of tea held by the financially troubled British East India Company in its London warehouses and to help the struggling company survive.  A related objective was to undercut the price of illegal tea, smuggled into Britain's North American colonies. This was supposed to convince the colonists to purchase Company tea on which the Townshend duties were paid, thus implicitly agreeing to accept Parliament's right of taxation. Smuggled tea was a large issue for Britain and the East India company, since approximately 86% of all the tea in America at the time was smuggled Dutch tea.  ​Colonists in the Thirteen Colonies recognized the implications of the Act's provisions, and a coalition of merchants, smugglers, and artisans similar to that which had opposed the Stamp Act 1765 mobilized opposition to delivery and distribution of the tea. The company's authorised consignees were harassed, and in many colonies successful efforts were made to prevent the tea from being landed. In Boston, this resistance culminated in the Boston Tea Party on December 16, 1773, when colonists (some disguised as Native Americans, since they identified themselves as “Americans” and no longer considered themselves British subjects[2]) boarded tea ships anchored in the harbour and dumped their tea cargo overboard.