This is a world where the Normans of Sicily and France/England became one united empire. Along with Castile, they colonized the New World (the Treaty of Oviedo split the Americas north and south between them). Irish refugees, fleeing the Norman takeover of their island in the 15th century, fled to *North America and established a state along the *St. Lawrence River.
Poland, meanwhile, stayed strong and created a globe-spanning trade empire, sort of like the Dutch of OTL writ large. As the 20th century dawned, the world had been wracked by a nuclear conflict between the Ottoman and Chinese empires (both industrialized in the early 18th century). A movement called Collectivism (think Communism combined with Freemasonry), created by a Bulgarian called Vasceny, spread throughout the broken remains of the former superpowers, and by 1960, the two nations were strong once more... and this time, they were allied.
The Triple Alliance of Normandy, Castile, and Poland is all that stands between freedom and complete Collectivist victory.