Over a 30-year period, the Hague marine painter Hendrik Willem Mesdag 1831-1915 purchased over 800 works of art. The outcome of this feverish activity can still be found in the museum he founded in The Hague. Built by Mesdag in 1887 as an annex to his house and studio in order to accommodate his growing collection, it was donated to the Dutch state in 1903 together with its contents of more than 360 paintings and drawings. Roughly half the works were by his contemporaries of the Hague School, while most of the rest are by artists of the School of Barbizon and French Realists: 12 Corots, 25 Daubignys, 12 Rousseaus, 7 Millets, 7 Courbets, and numerous works by Diaz, Dupre, Troyon, Decamps. It has been hailed as the most important Barbizon collection outside France. Being a painter's choice, the collection is idiosyncratic in its preference for sketchy paintings that show the artists engaged in the process of creation.