To help us reconstruct his family background, as well as his economic and artistic life, there are roughly fifty written documents, mostly kept at the Viseu District Archives and the Torre do Tombo, in Lisbon.

The basis for identifying the creative process of the grand master of the Portuguese Renaissance, or the works that are definitely known to have been produced by Grão Vasco, are the two paintings that he signed – the Lamentation with Franciscan Saints, dating from roughly 1520, known as the Cook Triptych because it was sold to an English collector, which is currently to be found at the Museu Nacional de Arte Antiga, and the altarpiece with the theme of Pentecost, painted in 1535, which is kept at the sacristy of the Igreja de Santa Cruz de Coimbra – as well as the five panels remaining from the former altarpiece of the chancel of Lamego Cathedral, exhibited in the museum of that city, and the magnificent Saint Peter of this collection, painted around 1529 for Viseu Cathedral.

Working with a highly personalised and easily characterisable artistic language, which can be defined by his use of a darker palette than the other Portuguese painters of his time, yet nonetheless one that had infinite gradations of tone, his sensitive use of light fundamentally to represent space in depth and to spatialise the form, the extraordinary plasticity of the fabrics, the powerful characterisation of the faces and the dramatic involvement of the figures, the realism and minute descriptive detail of scenarios and ornaments, habitually making use of simple objects from family life, Grão Vasco is a central and deservedly major figure in the history of Portuguese painting.

The economic importance of the dioceses of Viseu and Lamego, the social, political and cultural prestige of their bishops, members of the prime nobility and advisers to the king, the region's powerful religious centres, the success enjoyed by painting at the time, and, of course, the painter's artistic merit, all these factors enabled his workshop to be transformed into one of the country's most important centres of production.

In fact, after 1520, besides Vasco Fernandes, there were various painters active in Viseu, related both professionally and by ties of kinship, who followed his artistic development closely.