Both structures form a monumental area of great importance.

The origins of Suso Monastery date back to the late 5th century. Legend states that San Millán lived as an anchorite in the caves on which today stands the cloister, where the saint was buried in 574. Built against the caves, the primitive Visigothic Church of the 6th century, can still be seen. It has 2 naves and a Mozarabic portal from the 10th century.

The village that was named after San Millán declared him saint before the Church did, and San Millán´s Monastery was built in his honor. As a consequence, there was a constant flow of pilgrims who came to San Millán´s Sepulchre. From that moment the Monastery of San Millán de Suso became more and more important.

The second Monastery of San Millán, Yuso, has also a legendary origin. In the middle of the 11th century King García Sánchez ordered the construction of the Monastery of Santa María la Real in Nájera. The King, the Bishop and the Noblemen found it convenient to move San Millán´s relics to this church. The local chronicle tells that when the King was going to carry out the transfer,something unexpected happened: once the saint´s remains were in the cart pulled by oxes and the retinue were down on the valley, the animals stopped dead and no man on earth could make them move backwards or forward.

The King understood that it was a divine message and decided to build another monastery in the place where the animals had stopped: the Monastery of San Millán de Yuso (from the Latin deorsum, which means "down"). The other Monastery was called San Millán de Suso (from the Latin sursum, that means "up").

Yuso Monastery is noted for its great dimensions. It is the result of many centuries of architectural activity (founded in the 11th century, rebuilt in the 16th, 17th and 18th centuries) where different styles combine (Renaissance, Baroque...). Its interior also houses many works of art.