Located on the site of original entry of the Muslim fortress of Almanzor (10th century - the original defensive towers are still preserved within the walls of the gate), it was built from 1634 resulting from the initiative of the Rector of the University, Don Alvaro da Costa (1633-1637), and is the first major work of the University following the acquisition of Royal Palace to King Philip I.
Authored by Antonio Tavares architect, it presents us the main figures of the University the Kings D. Dinis and D. João III topped by the figure of Wisdom, the insignia of the University. In each of its portals, symmetric, we also find representations of the ancient colleges - Medicine and Laws on the outside, Theology and Canons inside. All sculptural groups are authored by Manuel de Sousa of authorship.
The Iron Gate is also one of the most important places of the academic life that developed around the University.