| Philip I | 
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| Reign | 11 July 1509 – 31 March 1567 | 
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| Predecessor | William II | 
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| Successor | William IV (Hesse-Kassel) Louis IV (Hesse-Marburg)
 Philip II (Hesse-Rheinfels)
 George I (Hesse-Darmstadt)
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| Born | 13 November 1504 Marburg, Landgraviate of Hesse, Holy Roman Empire
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| Died | 31 March 1567 (aged 62) Kassel, Landgraviate of Hesse, Holy Roman Empire
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| Spouse |  | 
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| Issue | 
Agnes, Electress of Saxony, then Duchess of SaxonyAnna, Countess Palatine of ZweibrückenWilliam IV, Landgrave of Hesse-KasselPhilipp LudwigBarbara, Countess of Württemberg-Mömpelgard, then Countess of WaldeckLouis IV, Landgrave of Hesse-MarburgElisabeth, Electress PalatinePhilip II, Landgrave of Hesse-RheinfelsChristine, Duchess of Holstein-GottorpGeorge I, Landgrave of Hesse-DarmstadtPhilipp, Count of DietzHermann, Count of DietzChristopher Ernst, Count of DietzMargretha, Countess of DietzAlbrecht, Count of DietzPhilipp Konrad, Count of DietzMoritz, Count of DietzErnst, Count of DietzAnna, Countess of Dietz
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| House | House of Hesse | 
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| Father | William II, Landgrave of Hesse | 
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| Mother | Anna of Mecklenburg-Schwerin | 
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| Religion | Lutheran (since 1524) Roman Catholic (until 1524)
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| Signature |  | 
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Philip I, Landgrave of Hesse (13 November 1504 – 31 March 1567), nicknamed der Großmütige (lit. 'the Magnanimous'), was a German nobleman and champion of the Protestant Reformation, notable for being one of the most important of the early Protestant rulers in Germany. He was one of the main belligerents in the War of the Katzenelnbogen Succession.