Great Britain’s victory over France in the Seven Years’ War, also known as the French and Indian War, gave it control over all of eastern North America. In an attempt to further flex their dominance in the New World, King George III issued a royal proclamation on October 7, 1763, which established three new mainland colonies (Quebec, West Florida and East Florida), extended Georgia’s southern border and gave land to soldiers who had fought in the Seven Years’ War. Most notably, the Proclamation of 1763 banned settlement west of the Appalachian Mountains, infuriating colonists—including George Washington.

Most native tribes had allied with the French during the conflict, and they soon found themselves dissatisfied by British rule. In May 1763, just a few months after the formal conclusion of the Seven Years’ War, a pan-tribal confederacy led by Ottawa chief Pontiac rose up in rebellion. His warriors attacked a dozen British forts, capturing eight of them, and raided numerous frontier settlements. Hundreds died in the process. In response, the British handed out smallpox-infected blankets to Pontiac’s followers. Moreover, a gang of whites known as the Paxton Boys massacred 20 defenseless Native Americans who had nothing to do with the fighting.

In an attempt to prevent similar incidents from occurring, King George III issued his royal decree. Acknowledging that “great frauds and abuses have been committed,” the proclamation furthermore prohibited settlers from buying tribal territory. Instead, only the crown could now make such purchases. “We shall avoid many future quarrels with the savages by this salutary measure,” said General Thomas Gage, who commanded all British forces in North America.

The British made a perfunctory effort to enforce the proclamation, periodically stopping settlers as they headed west and forcibly removing others. On one occasion, redcoats from Fort Pitt in present-day Pittsburgh even burned the huts of some nearby pioneers and escorted them back across the boundary. For the most part, though, colonists disregarded the proclamation without fear of punishment. Some wanted only enough land for themselves and their families, whereas others were speculators looking to make a hefty profit down the road. George Washington wrote to his agent in 1767 in support of illegally buying as much Native American land as possible. The Proclamation of 1763 will soon be revoked, Washington explained, because—“this I say between ourselves”—it was only meant “as a temporary expedient to quiet the minds of the Indians.” Other famous speculators included Patrick Henry, best known for his “Give me liberty or give me death” speech, and Henry Laurens, who later served as president of the Continental Congress.

Washington’s prediction proved prescient the following year when the British moved the boundary line westward as part of the Treaty of Fort Stanwix. Under the deal, the Iroquois agreed to give up parts of present-day New York, Pennsylvania, Kentucky, Tennessee and West Virginia in exchange for cash, gifts and the (soon-to-be-broken) promise of a permanent border. But although the Iroquois claimed those lands, they did not live there. The tribes that did, such as the Shawnee, were infuriated, and ended up going to war with the British in 1774. Meanwhile, further south, the Cherokee surrendered tens of thousands of square miles in a series of treaties. Also losing territory were the Creeks, who purportedly referred to the colonists as Ecunnaunuxulgee, or “People greedily grasping after the lands of the red people.”

Ultimately, the new acquisitions failed to quiet colonial discontent with the Proclamation of 1763. And though it would be later overshadowed by other complaints against the British, such as the Sugar Act, the Stamp Act, the Townshend Acts, the so-called Intolerable Acts and the Boston Massacre, it remained enough of a concern that the Declaration of Independence criticized King George III for “raising the conditions of new appropriations of lands.” By winning their freedom from the British in 1783, the Americans rendered the proclamation moot. But it has lived on to this day in Canada, where it forms the legal basis for native land rights. “We must recall the intent that brought all our ancestors together so many years ago,” Shawn A-in-chut Atleo, national chief of Canada’s Assembly of First Nations, said at a 250th-anniversary event in 2013, “and ensure that [we live up] to the promises in the treaties and other agreements that stem from the foundation of the royal proclamation.”