Several theories abound as to why the Norse settlements in North America failed and vanished. One theory postulates that they were wiped out or driven out by the native-Americans. This theory further claims that it all started with Native Indians being lactose intolerant. At some point during first contact, a Norseman gave a native Indian a drink of milk as a gesture of friendship. Needless to say things just go down hill from there with the Indians thinking they were poisoned. POD Assuming the above theory is true let's Suppose Native Americans are were Lactose intolerant, in fact they freely accept milk and other dairy products as an addition to the native diet? Norse and Natives get along relatively well and trade ensues giving the Greenland and Vineland colonies support from the local natives about how to survive the harsh winters. The result is that the Spanish explorers meet a well organized, firearm equiped, VNA infantry and calvary when they arrive in the West Indies. The Britsih and French in Noth America have a similar experience. IOW, no Western Hemisphere Spanish Empire, no French and British North American colonies, and no North American conflicts between them. Some trading posts perhaps, but no 'gunpowder' superiority over the Native Americans. The discussion should center on how Europe develops from the 1500s onward without North/Central/South America to expand into and the wealth derived from the Americas. I know that a similar theme was covered in a novel whose name and author I forget, but that was based on Europe being almost completely depopulated by a plague, resulting in there being no European country able to 'discover' and colonize the New World, and an Asian presence in North America.