Philipp was a son of
John I, Count of Nassau-Weilburg (1309 – 1371) and
Johanna, Countess of Saarbrücken (d. 1381), daughter of
John II, Count of Saarbrücken (d. 1381). Philipp inherited the
County of Nassau-Weilburg from his father in 1371 and the
County of Saarbrücken from his mother 1381. For the first ten years, his mother was the regent in his place, then bishop
Friedrich of Blankenheim was the regent until his majority. Philipp married twice and had several children, and his first wife Anna brought some territories in
Trier that were added to his realm. At Philipps death in 1429, the counties were ruled jointly by his eldest sons, with their mother Elisabeth as regent until 1442, then it was divided between them,
Philipp getting Nassau-Weilburg and
Johann getting Saarbrücken and Commercy. At Philip's majority in 1438 he began ruling in collaboration with his mother, and provisions were made for her future. In the war 1387–1389
(de) Philipp sided with the
Bavarian duchies, against the
Swabian union
(de). For his achievements at the battle of Döffingen
(de) he was honoured with the
accolade. His involvement gave important allies and influence in southern Germany. In 1398 he was accredited with the privileges of coinage by
Emperor Wenceslaus, and the power of his realm was consolidated. The emperor appointed him also to supervise the "
landfrieden" in
Rhine and
Wetterau areas. In the national politics he both collaborated in the removal of emperor Wenceslaus 1400, protecting his successor
Rupert and then joining many other lords in the opposition against him 1405–07, and until his Rupert's death in 1410. He participated at the crowning of the successor,
Sigismund, Holy Roman Emperor, who elevated him, and made him a member of his council, and "Hauptmann" (leader) of the nobility in
Luxembourg. He was
also a member of the council of the French king. At the
Council of Constance, Philipp supported King Sigismund against the policies of certain Popes, at the time of the
Western Schism. ==Marriage and issue==