Michiel Van Mierevelt (Delft 1567–1641) produced many portraits of the important contemporary Dutchman, Prince Maurits. Two panel paintings dated 1607 are his earliest paintings of the prince. One of these was painted for the Delft City Hall, now housed in the Stedelijk Museum Het Prinsenhof, Delft (PDS 68b). This painting is considered to be the ‘first’ portrait, which was repeated by Van Mierevelt and his assistants over a hundred times. The painting technique used in the portrait is unusual, with a layer of earth pigments and lead minium in oil applied directly onto the panel. The traditional chalk glue ground is absent, as Van Mierevelt desired an orange coloured ground, to give subsequent paint layers a deep saturation and a warm glow. This transparent ground also allows the colour of the panel to shine through. The slow drying aspect of the oil ground was speeded up by the lead minium. The ground does not level out the panel structure however, the wood grain is distinctly visible in the paint surface. For the face Van Mierevelt randomly applied a white underpainting, onto which he transferred an underdrawing using a pounced carton. In the early portraits of Maurits, Van Mierevelt used a painting technique adapted for rapidly making many optically impressive paintings. Later paintings in the series are more in line with the traditional techniques of the time, in part because of the input of studio assistants.