Right next to the Micalet is the "Iron Gate" due to the iron grille that surrounds the entrance atrium. It is the most modern and the main one, begun in 1703 by the German sculptor and architect Konrad Rudolf.
This gate is of notable interest for its successful and daring approach within the Hispanic context of the time. It is one of the few examples of the application of Italian architectural baroque, with an undulating and moving plan, in the style of Bernini or Borromini, unlike the Spanish Baroque buildings of the time, of the Xorigueresque type, with a traditional plan and great decorative profusion.
The Iron Gate, which resembles a concave altarpiece, is more than 36 meters high. When it was built, it was intended to create the optical illusion of a greater sense of space in a really small place —in the manner of Bernini or Borromini—, since it was conceived to be seen from the narrow alley (of Zaragoza) that led to it. Today, this street has disappeared when the Plaza de la Reina was widened, and its twisted shape in a large square is completely incomprehensible.
The Iron Gate, which is preceded by an atrium that limits an iron grille, also baroque, unfolds in three superimposed bodies.