This painting is not a portrait. The skull held by the boy is a reminder of the transience of life and the certainty of death. Such a subject is known as a 'Vanitas' (Latin for vanity), a name derived from a verse in the Old Testament (Ecclesiastes 12: 8), 'Vanity of vanities, saith the preacher, all is vanity.'
The Netherlandish tradition of showing young boys holding skulls is well-established and can be traced back to engravings of the early 16th century. The exotic clothing recalls that used in allegorical and genre subjects by the Utrecht followers of Caravaggio, the so-called 'Caravaggisti'. The painting can be dated to around 1626/8.