The Frans Hals Museum operates from two sites in Haarlem, the Netherlands, that were united under the Frans Hals Museum name in 2018: the Hof and the Hal. The Hof houses works collected by the city beginning in the 1600s and the Hal exhibits contemporary art. In 2013, the museum celebrated its centennial; Curator of Modern Art Antoon Erftemeijer stated that because the collection at the Frans Hals Museum was established over 400 years ago, it could be called the "oldest art museum in the Netherlands." The online collection allows visitors to explore digital versions of over 12,000 artworks and historical objects and can be browsed by color, time period, medium, and artist. There are also listings for current exhibitions, such as Museum in Bloom, where floral arrangements are paired with works of art throughout the museum. Another current exhibit is Haarlem Heroes: Other Artists, which includes additional artists whose work make up the collections, such as Judith Leyster's Portrait of an Unknown Woman, 1635. The museum's website is highly optimized for mobile viewing; for some viewers, the site may be easier to use on a phone or tablet than a computer.