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Taxation sounds to noble, but it was really the prevention of colonial expansion into Native territory that pissed off the colonists.
The Royal Proclamation of 1763 was issued by King George III on 7 October 1763. It followed the Treaty of Paris (1763), which formally ended the Seven Years' War and transferred French territory in North America to Great Britain.[1] The Proclamation forbade all settlements west of a line drawn along the Appalachian Mountains, which was delineated as an Indian Reserve.[2] Exclusion from the vast region of Trans-Appalachia created discontent between Britain and colonial land speculators and potential settlers. The proclamation and access to western lands was one of the first significant areas of dispute between Britain and the colonies and would become a contributing factor leading to the American Revolution.[3] The 1763 proclamation line is situated similar to the Eastern Continental Divide, extending from Georgia to the divide's northern terminus near the middle of the northern border of Pennsylvania, where it intersects the northeasterly St. Lawrence Divide, and extends further through New England.
https://en.wikipedia.org/wiki/Royal_Proclamation_of_1763
Crimes were to the East were judged by colonial law, crime to the West faced Native American justice.
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