The world’s oldest diplomatic alliance

For more than six centuries, Portugal and Great Britain have called each other allies. The Alliance is a documentary that traces this history, little known outside specialist books: the Treaty of Windsor of 1386, the Anglo-Portuguese marriage that sealed it, the gold of the Methuen Treaty, the British armies that helped expel Napoleon — and the price Portugal paid for that protection. From the near-colonial dependency of the early 19th century to the national trauma of the 1890 Ultimatum, from the Great War to the discreet complicities of the 20th century, the documentary follows the moments when this alliance was tested, challenged, and reinvented.