It happened today - June 13, 2016

Marriage of John I, King of Portugal and Philippa of Lancaster, daughter of John of Gaunt, 1st Duke of Lancaster. (Wikipedia)

Quick. Who is Britain’s oldest ally? You don’t get to answer if you’ve watched my documentary The Great War Remembered. Or if you’re from there. But odds are you’re not because it’s a fairly small country not ranked among the global heavyweights. The answer is (drum roll please)… Portugal.

The Treaty of Windsor creating the Anglo-Portuguese Alliance was made so long ago it wasn’t even Britain but England that signed it in 1386, updating a document from 1373. And it helped both. Portugal of course had fairly simple strategic problems through much of its history, even when it was an empire. OK, one fairly simple strategic problem. Spain. Which did actually contrive to swallow Portugal between 1580 and 1640, interrupting but not destroying the alliance.

England had more complicated problems. But Spain was one of them, from the time that the Hapsburgs threatened to dominate Europe from Spain to the time that Napoleon threatened to dominate Europe including Spain. And indeed the Portuguese did contribute on the Western Front in WWI after the Germans attacked their African possessions, thus having their own military cemetery near Neuve Chapelle with tombstone after tombstone reading “Soldado Portuges Desconhecido”.

Portugal did not enter World War II because they and the British agreed that doing so would bring Spain in on the other side which would have been disastrous for both. But Portugal did grant the British naval bases in the Azores.

If you like dynastic things, you will be happy that John of Gaunt, son of Edward III and father of Henry IV of England, married his daughter Philippa to King John I of Portugal in 1387 and thus the Portuguese royals in the Age of Discovery were part-English even if the nobles did find Philippa rather strait-laced by their standards. And it’s also noteworthy that the English had even helped the Portuguese reconquer parts of their land from the Moors in the 12th century. Some friendships endure even in geopolitics.

Nowadays the UK and Portugal are both in NATO and unlikely to go to war together except as part of that alliance. But it’s nice that some things last.

Oh, this alliance also helped bring the world port. Which is a lot more than you can say on the positive side about most diplomatic agreements.