It was designed by Felipe Berrojo and built in 1662 to replace the previous Romanesque entrance which was in ruins. The N-120 road through Sahagún was planned to go under the arch as though it were a triumphal arch. Amongst the most outstanding architectural elements are the central coat of arms, inscriptions and statues. Also, the two statues of Saint Facundo and Saint Primitivo on the two niches.
On the upper part is a sculpture of the royal coat of arms, and sculptures of Alfonso III and Alfonso VI, two of the main benefactors of Sahagún.
It has been declared a National Monument and forms part of the Jacobean Route.