Philip IV, Count of Nassau-Weilburg

Philip IV, Count of Nassau-Weilburg
Philip's coat of arms shows the lions of Nassau and Saarbrücken
Spouse(s)	Erika of Manderscheid-Blankenheim Elisabeth of Nassau-Dillenburg
Noble family	House of Nassau
Father	Philip III, Count of Nassau-Weilburg
Mother	Amalie of Isenburg-Büdingen
Born	(1542-10-14)14 October 1542 Weilburg
Died	12 March 1602(1602-03-12) (aged 59) Saarbrücken
Buried	Collegiate Church in St. Arnual (now part of Saarbrücken)

Philip IV of Nassau-Weilburg, also known as Philip III of Nassau-Saarbrücken (14 October 1542 in Weilburg – 12 March 1602 in Saarbrücken) was Count of Nassau-Weilburg from 1559 until his death and since 1574 also Count of Nassau-Saarbrücken. Both possessions belonged to the Walram line of the House of Nassau. In Weilburg, he was the fourth count named Philip, but only the third in Saarbrücken, because his father, Philip III of Nassau-Weilburg never held Nassau-Saarbrücken.

Philip IV was the son of Philip III of Nassau-Weilburg and his third wife Amalie of Isenburg-Büdingen.

Philip IV and his older half-brother Albert of Nassau-Weilburg were educated in the Protestant faith by Kasper Goltwurm at Neuweilburg Castle. Philip later studied at the University of Jena, where he was rector for a while.

On 4 October 1559 his father died. Philip and Albert inherited the County of Nassau-Weilburg. As Philip was only sixteen years old, John III of Nassau-Saarbrücken, the senior member of the Walram line of the House of Nassau took up the guardianship. Initially, the brothers Albert and Philip ruled together. However, the huge debt they had inherited from their father curtailed their ability to act. Nevertheless, they managed to slowly improve their fiscal situation.

On 15 May 1561, the brothers split their inheritance for the first time. Albert received the castle and district of Weilburg, while Philip received Castle and district of Neuweilnau. The largest part of their territory and the father's the debt, however, remained common property. Philip moved into Neuweilnau Castle, which had already served his father as a residence. Between 1564 and 1566, he significantly expanded the castle.

Philip belonged to the Wetterau Association of Imperial Counts, in which Albert took a leading role. In 1567 and 1568, Philip met with William the Silent several times. He participated in the preparation of the Dutch War of Independence against Fernando Álvarez de Toledo, 3rd Duke of Alba. However, the attack on the Netherlands in 1568, failed.