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In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: Ruisdael's work from c. 1646 to the early 1650s, when he was living in Haarlem, is characterised by simple motifs and careful and laborious study of nature: dunes, woods, and atmospheric effects. By applying heavier paint than his predecessors, Ruisdael gave his foliage a rich quality, conveying a sense of sap flowing through branches and leaves. His accurate rendering of trees was unprecedented at the time: the genera of his trees are the first to be unequivocally recognisable by modern-day botanists. His early sketches introduce motifs that would return in all his work: a sense of spaciousness and luminosity, and an airy atmosphere achieved through pointillist-like touches of chalk. Most of his thirty black chalk sketches that survive date from this period.An exemplar of Ruisdael's early style is Dune Landscape, one of the earliest works, dated 1646. It breaks with the classic Dutch tradition of depicting broad views of dunes that include houses and trees flanked by distant vistas. Instead, Ruisdael places tree-covered dunes prominently at centre stage, with a cloudscape concentrating strong light on a sandy path. The resulting heroic effect is enhanced by the large size of the canvas, "so unexpected in the work of an inexperienced painter" according to Irina Sokolova, curator at the Hermitage Museum. The art historian Hofstede de Groot said of Dune Landscape: "It is hardly credible that it should be the work of a boy of seventeen".
Ruisdael's first panoramic landscape, View of Naarden with the Church at Muiderberg in the Distance, dates from 1647. The theme of an overwhelming sky and a distant town, in this case the birthplace of his father, is one he returned to in his later years.For unknown reasons, Ruisdael almost entirely stopped dating his work from 1653. Only five works from the 1660s have a, partially obscured, year next to his signature; none from the 1670s and 1680s have a date. Dating subsequent work has therefore been largely based on detective work and speculation.All thirteen known Ruisdael etchings come from his early period, with the first one dated 1646. It is unknown who taught him the art of etching. No etchings exist signed by his father, his uncle, or his fellow Haarlem landscapist Cornelis Vroom, who influenced his other work. His etchings show little influence from Rembrandt, either in style or technique. Few original impressions exist; five etchings survive in only a single impression. The rarity of prints suggests that Ruisdael considered them trial essays, which did not warrant large editions. The etching expert Georges Duplessis singled out Grainfield at the Edge of a Wood and The Travellers as unrivalled illustrations of Ruisdael's genius.
Output:
Where was Ruisdael's father born?