The first Large scale war the British Empire has ever faced began 1626, spanning four different continents, North America, South America, Africa and even Europe itself, with a possibility of British Australia facing off Aragon's New Zealand
North American Front:
Governor Nuclear Kid was jumping for joy when he was ordered to invade the Portuguese colonies in North America, after one battle with 1000 Portuguese Vs. 13,000 British the Portuguese colony was left open for the taking, meanwhile the Aragon army marched into British holdings in the Dominican region only to be repelled by the British once again
South America:
The Army of Castile marched into the British holdings in south America unopposed
Europe:
So far no land battles have occurred but the sea battle is heating up, Admiral Nodikus has defeated the combined Navies of Portugal, Castile and Aragon in three different battles and has captured two enemy Carracks, however the damage began to stack up and forced the British Navy to dock for repairs in Brittany, the Iberians took the opportunity to blockade the British Isles
North Africa:
after an agreement with France to allow British forces free passage through France holdings in Africa, British troops fresh off the Persian front marched into Tripoli, an ally of the Iberians, and have occupied half the country, knocking one of enemy nations out of the war within the first months of the war
Blue=Iberian Movement
Red=British