From 1452 until the county was divided in 1458, the regency was exercised by a council, consisting of his maternal grandfather Count Palatine Otto I of Mosbach, his paternal grandmother, Katharina of Nassau-Beilstein, and his only uncle, Philipp the Elder.

This situation presented the Hanau family with a dilemma: The debate over the division of the county is relatively well documented.

He supported the interests of his daughter Margaret, the widow of Reinhard III and the mother of Philipp the Younger.

She held that the danger of the House of Hanau dying out could be reduced by allowing Philipp the Elder to marry, since he had already proven his ability to procreate.

Relatives of the Count and the most important organizations among their subjects — in particular the four cities in the county, Hanau, Windecken, Babenhausen and Steinau, and the associations of the Burgmannen of Babenhausen Castle and the Palatinate of Gelnhausen — as well as the vassals of the Counts of Hanau, all wrote to Otto I and requested that Philipp the Elder be allowed to marry.

When his daughter Margaret died in 1457, Count Palatine Otto I no longer had a reason to oppose the division.

Philipp the Elder received the part of the county south of the river Main, that is, the district of Babenhausen and the Hanau share of Umstadt.

He wrote an account of the journey, which, however, largely consists of an exhaustive list of holy sites he visited and the indulgences he acquired.

During the reign of Philipp the Younger, Hanau-Münzenberg made significant territorial gains: In 1470, Praunheim was acquired, in 1476 a share in the district of Ortenberg, in 1473 or 1484 Fechenheim and in 1487 Homburg.

In 1474 and 1475, he participated with a contingent of troops on the side of Emperor Frederick III in the relief of the city of Neuss, which was being besieged by Charles the Bold.

He donated generously to religious institutions; he made two pilgrimages to the Holy Land and he collected relics.

He purchased the entire collection of relics from the monastery at Seligenstadt when it was in financial distress, including the head of St. Lawrence.

Erasmus Hasefus, Philipp's trumpeter, founded in 1468 a chapel in the Bulau Forest, dedicated to St. Wolfgang.

Philipp the Younger also appears to have had a pre-marital affair with a Gutte from Reifenberg, who was the maidservant of the priest of Hochstadt and Reinhard IV.

Philipp the younger died on 26 August 1500 and was buried in the Church of St. Mary in Hanau; 214 clergyman were present at his funeral.

The Protestant scholars of the 18th Century objected to his late medieval piety, fixated on indulgences, relics and good works.

The St. Mary's Church, the "Gotha Lovers" and the "Wörth altar piece" are the most outstanding testimonies of the cultural achievements under his government, and have remained remarkable works of art.