From the museum website
The Museo del Prado is continuing with its Invited Work programme, which introduces visitors to major works from other collections. Its aim is to enrich a visit to the Museum and establish comparisons with works from the Prado’s own collection. The Rijksmuseum has generously lent one of its masterpieces, The Company of Captain Reinier Reael, painted by 1637 by Frans Hals and Pieter Codde.
This portrait of 16 militiamen is an important example of the genre of portraits of militia companies that was widely found in Dutch painting throughout the 17th century. In 1670 Jan van Dijk nicknamed the painting The “thin” Company due to the skinny appearance of the sitters.