Input (grade 13): The Douro valley where Port wine is produced was defined and established as a protected region, or appellation in 1756 - making it the third oldest defined and protected wine region in the world after Chianti (1716) and Tokaj (1730).
Output (grade 8): The Douro valley where Port wine is produced was defined and established as a protected region, or appellation in 1756. It is the oldest defined and protected wine region in the world.