What medieval gate was the Bastille originally built to defend?

The medieval gate the Bastille was originally built to defend was the Porte Saint-Antoine.

The Porte Saint-Antoine stood at the eastern edge of medieval Paris, where the route now associated with the rue Saint-Antoine led beyond the city’s walls. Its position made it a strategic entry point: an enemy approaching from the east could threaten both the gate and the royal residences in the Marais.

The fortress began as a defensive work connected with that gateway. Charles V ordered major eastern fortifications after the disturbances of the 1350s, and construction of the Bastille began in 1370 under the direction of the Parisian provost Hugues Aubriot. Completed in the early 1380s, it became a powerful fortress guarding the approach and helping protect Paris.

The Porte Saint-Antoine and the Bastille were related but not identical structures. The gate was an opening through the city’s wall; the Bastille was the large fortified stronghold beside it. Later alterations changed the gate’s layout, and both the fortress and the medieval gateway eventually disappeared, although their outlines remain marked in the paving of today’s Place de la Bastille.