
Okay, this is an idea I came up with based on the legend that the Knights Templar discovered America in the 1300's. I know, weird, right? Nope, there's actually some convincing evidence.

Scottish noble Henry Sinclair, Earl of Orkney, who was supposedly a Knight Templar, might have discovered America in the 1390's. In this timeline, I imagine Sinclair's voyage much the same way as it supposedly happened, but as soon as he lands, the breakpoint occurs. And no, La Merika is NOT made up by me. :O
Here we go! ^_^
October 25th, 1397: Henry Sinclair and a group of Knights Templar and Scandinavians land in Nova Scotia, fleeing persecution. The Templar were officially disbanded years before, but there were some who still hung on to the old ways. They followed Phoenician charts captured from the Temple of Solomon during the Crusades. The charts speak of a land that can be found by following a star named "La Merika." They establish an encampment in what we know as Yarmouth in our history.
October 26th, 1397: The encampment receives visitors. 30 natives from the Micmac tribe appear from the woods. Immediately, the Templar draw their weapons and frighten them off. It's just the beginning of tensions.
October 27th-November 20th, 1397: The knights construct a log wall around their base and raise the Templar and Scottish banners in the center of the fort. Natives watch the progress in amazement.
November 21st, 1397: Sinclair allows five natives to trade with his men. Steel axes and shields are exchanged for pelts and trinkets. The natives have an intense dislike of the Europeans after one of the Templars has a fist fight with an Indian trying to steal a sword.
November 25th, 1397: Sinclair and his men hunt in the nearby woods. They spot many unusual animals and plants. Sinclair writes a letter for his friends in Europe to cross the Atlantic. A small crew boards one of their ships and heads back to Europe to deliver it. The message reaches Templar mercenaries in Scotland and King Eric of Pomerania.
May 11th, 1398: A massive fleet of Knights Templar, European outlaws, outcasts, adventurers, and various monks, along with a small army from Pomerania, arrives. Sinclair's men are overjoyed.
May 15th, 1398: A Pomeranian soldier kills a native after he finds him breaking into the fort armory. Violence breaks out.
May 16th, 1398: The fort is christened New Inverness, after Inverness, Scotland. Sinclair leads a joint force of Templar cavalry and Pomeranian infantry into battle against the natives. The natives are beaten badly, and retreat in disorder.
May 17th, 1398: Templar soldiers attack a Micmac village, loot it, and burn it to the ground. The Indians seem helpless against the growing numbers of Europeans.
May 20th, 1398: Pomeranian troops occupy what we know as Digby by defeating a substantial force of natives. They name it Nova Pomerania.
June 12th, 1398: Europe is in a state of shock after word reaches the Pope that the "dastardly Templars" had established a colony across the ocean. Immediately, nations, particularly the ones most loyal to the Pope, race across the Atlantic to grab territory. Even some rich nobles make the voyage for a chance at occupying unclaimed land and making themselves monarchs. Tinpot dictators, Scottish clansmen, and traders grab chunks of land in Greenland, Nova Scotia, and the north-eastern seaboard over the next years.
February 8th, 1400: Henry Sinclair is officially chosen as leader of Nova Scotia by a vote of hands from the remaining members of his original crew. The natives lose one last time to Sinclair's forces in an attack on Nova Pomerania. They are defeated utterly and Templar and Pomeranian soldiers hack them down as they attempt to escape. The reign of the Micmac is over.
February 25th, 1400: Scottish soldiers arrive at New Inverness. No matter what the Pope wants, the Templar have regained their strength and are a force to be feared. They have a monopoly on Nova Scotia, depriving loyal servants of the Church a chance to occupy it. Any loyal Catholics who have the guts to show up and try to make a profit from furs or land are promptly raided or taxed out of business.
Mid 1400: Europeans are still few, but they are growing in numbers very rapidly.
September, 1400: A Portuguese fleet discovers a part of what we call Florida, and names it New Coimbra, after a city in Portugal. The Pope dispatches several knights and nobles to spread the Faith to the natives.
January, 1405: The first primitive maps of Nova Scotia and the Eastern Seaboard are made. They are wildly inaccurate.
February 9th, 1405: Henry Sinclair dispatches an expedition to the main North American continent. They attempt to map what we now as Maine. The expedition consisted of 100 men, and returned with 47.