"William Louis of Württemberg (7 January 1647 – 23 June 1677) was the ruler of the senior Duchy of Württemberg from 1674 until his death in 1677.
William Louis was born in Stuttgart, the ninth child of Eberhard III, Duke of Württemberg, and his first wife Anna Katharina of Kyrburg.
At the age of 30, the Duke died unexpectedly of a heart attack at the stop-over in Schloß Hirsau. His widow Magdalena Sibylla became regent of Württemberg between 1677 and 1693, until her son reached adulthood." - (en.wikipedia.org 24.12.2019)
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