Cornelis or Cornelius Ketel (18 March 1548 – 8 August 1616[1]) was a Dutch Mannerist painter, active in Elizabethan London from 1573 to 1581, and in Amsterdam till his death.

[2] According to Ketel's biography, written by his contemporary Karel van Mander,[3] he seems to have wanted to concentrate on the most prestigious of the hierarchy of genres, history painting, which included mythological subjects, but after he left France he is known almost entirely as a portrait-painter.

[2] He did however significantly influence the development of the largest type of painting commonly produced in the United Provinces at this period, the civic group portrait.

[7] He returned to Gouda, but the economy there was severely hit by the occupation of the city in 1572 by the Geuzen rebels, followed in 1573 by a plague which killed 20% of the population and the Dutch Revolt which was entering a new phase that destabilised daily life throughout the Netherlands.

The biographer Karel van Mander notes his portrait of Sir Christopher Hatton,[8] of the Earl of Oxford, and various noblemen, their wives and children.

Karel van Mander records that Ketel was patronized by the prosperous German Hansa merchants of the Steelyard and that a Force overcome by Wisdom and Prudence commissioned from him and presented to Sir Christopher Hatton introduced him to court circles.

In 1577 Ketel was commissioned to paint a series of 19 portraits for the Cathay Company, one of which is the famous (but very damaged) full-length of Martin Frobisher now in the Bodleian Library.

[18] Recently, a series of head-and-shoulders paintings of members of the family of Thomas "Customer" Smythe dated 1579, now widely dispersed, has been identified as the work of Cornelis Ketel.

Some of Ketel's history paintings are documented in various ways, including a Democritus and a Heraclitus copied very brilliantly by Rembrandt aged around thirteen, when he was training with Pieter Lastman in Amsterdam.

[22] Ketel's 1588 The Company of Captain Rosecrans, the earliest Dutch group portrait where the figures are shown standing and full length, "greatly influenced later artists of militia pieces, such as Rembrandt in his Night Watch of 1642.

[25] The picture has been trimmed on all sides, especially above; originally the city gate in front of which the group are standing was much more prominent, and in this respect closer to the Night Watch.

[2] Together with Pieter Pietersz, Ketel was the leading portraitist in Amsterdam for many years, and one of the generation of Dutch portrait-painters whose increasingly sophisticated work laid the foundations for their much more famous successors.