Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Example input: In 1582 the united provinces invited francis, duke of anjou to lead them; but after a failed attempt to take antwerp in 1583, the duke left the netherlands again. after the assassination of william of orange (10 july 1584), both henry iii of france and elizabeth i of england declined the offer of sovereignty. however, the latter agreed to turn the united provinces into a protectorate of england (treaty of nonsuch, 1585), and sent the earl of leicester as governor-general. this was unsuccessful and in 1588 the provinces became a confederacy. the union of utrecht is regarded as the foundation of the republic of the seven united provinces, which was not recognized by the spanish empire until the peace of westphalia in 1648.
Example output: In what year did francis, duke of anjou leave the netherlands?
Example explanation: The generated question is perfect. Because the question is based on second sentence of the input passage and its answer is 1583.
Q: The article briefly summarizes the milestones leading to current knowledge and the possibility of treating one of the most widespread and perhaps least known diseases, restless legs syndrome (RLS). Until the mid-twentieth century, the syndrome first described by Willis (1685), was sporadically reported in medical literature and in most cases deemed a bizzare condition. It was only with Ekbom's detailed clinical description of the syndrome (1944) and the polygraphic recordings of Coccagna et al. (1962) that RLS became well-recognised clinical entity. Since then, almost all sleep laboratories have devoted much of their research to discovering the pathogenetic mechanisms underlying the disease and devise increasingly specific treatment. Major advances have been made in recent years, but a full understanding of RLS is still a long way off.
A:
Willis-Ekbom disease is also known as?