"The Pórtico da Gloria (The Porch of Glory)"

It is not known where Mateo began to train as an architect and sculptor, but he caught the attention of King Ferdinand II of León when he was young and he commissioned him to continue the work on the Cathedral of Santiago. Mateo took charge of the work in 1168, when he was between 25 and 30 years old, with a lifetime contract and the most substantial salary.

Although this masterpiece of Romanesque architecture began so young, no previous works are attributed to him. This draws attention, since the fact that he was hired for one of the most important temples of Christianity, and in those conditions, seems to indicate that he was already well known before taking on this work. He  traveled and worked in France, when the first Gothic cathedrals were being built. Surely Mateo entered architecture working in the quarries, knowing the stone and its secrets in depth so that it would not fall apart when building those tall cathedrals.

This education in French Gothic fits in with his later contributions to the Cathedral of Santiago, which are mixed with others more typical of Galician Romanesque and the rest of the Peninsula. Some references to him appear in written documents. In addition to the contract he signed with Ferdinand II, a "magister Matheus" is mentioned in a carving on the lintels of the Pórtico de la Gloria. 

Popular belief recognizes the figure of “Santo dos Croques” (Saint of the Head Bumps) as the self-portrait of Master Mateo himself. It is a sculpture kneeling behind the mullion, which is given that name due to the custom of giving it a small bump on the head when passing by it. Actually, this has been denied: he is not identified with Master Mateo, but with a pilgrim who reveres the temple he is about to enter.