Martin of Tours (c.316-c.397) was venerated throughout the Netherlands. He is normally shown in armour as a young cavalry officer in the Roman army serving in Gaul, although in this depiction he wears a broad plumed hat more typical of sixteenth century fashions. On a winter's day Martin encountered a poor beggar at the city gate of Amiens and cut his military cloak in half with a sword, giving half to the beggar. That night St Martin dreamed that Christ came to him wearing the piece he had given away.

This painting is a larger variant of a version in Zaventem, which was painted for Ferdinand van Boisschot, Baron of Zaventem and which became Van Dyck's best known painting in Flanders. That picture probably served as the starting point for the Royal Collection painting and the composition was altered in several stages, for example the group of beggars was extended to include a woman and two children and a dog, and the head of a second beggar woman on the right hand side was completely overpainted. The poses of the main figures in the two pictures are also not identical.

Anthony van Dyck was Rubens's most gifted pupil and assistant. Both the Royal Collection picture and the Zaventem one were probably painted while Van Dyck was working in Rubens's studio in Antwerp. The composition is very much in the style of Rubens with a smooth and highly finished surface and may have been based on a Rubens sketch or ideas. This version probably remained behind in Rubens's studio when Van Dyck left in 1620 and the numerous copies made suggest that it was available there for painters in Antwerp to copy.