There is little personal information on Herod's third heir except the name of his mother [Cleopatra of Jerusalem] & the fact that the king's will (4 BCE) made him administrator of Gaulanitis [Golan], Batanea & Trachonitis, regions in southwestern Syria & the Lebanese mountains that Augustus had added to Herod's jurisdiction two decades earlier (23-20 BCE). Like the territory assigned his half-brother Antipas, Philip's domain comprised about a quarter of the area of Herod's kingdom & was the least heavily Judaized. Like Antipas, Philip honored his Roman patrons by founding cities dedicated to the imperial family. Paneas, an ancient spa & pagan shrine at the source of the Jordan river, became Philip's imperial capital [Caesarea Philippi], while the fishing port of Bethsaida on the northeast shore of Lake Gennesaret was enlarged & renamed Julias to honor the wife of Augustus [Livia, who styled herself Julia Augusta]. He was married to Salome II, who was daughter of his half-brother Herod II by his niece, Herodias. But he died without heirs & his domain was given to Herodias' brother, Agrippa I.

Secondary literature, such as Easton's Bible Dictionary, has often referred to him as "Herod Philip" although there is absolutely no evidence in primary sources that he mimicked his half-brother Antipas in claiming his father's name or was addressed as Herod by contemporaries. This is a convenient modern convention to distinguish him from other ancient Hellenized rulers with the same given name.

References: Josephus, Antiquities 17.21, 27, 146, 189, 318-319; 
                                                        18.106-108, 137, 237. 
                   _____, War 2.94-95, 168.
                   Luke 3:1

Other resources on line:

• Philip - brief biography by Jona Lendering with map of Philip's tetrarchy [Livius: Articles in Ancient History].

• Philip the Tetrarch - brief entry in Wikipedia's web.

Coin minted at Caesarea Philippi in the 34th year of Philip's reign [ =30 CE, the probable year of Jesus' crucifixion] about the time of Jesus' reported visit to villages in that region [Mark 8:27 // Matt 16:13]. The image on the face of this coin is unusual in that it depicts Tiberius without the imperial diadem.  The poorly struck Greek inscription reads (clockwise from left of bust) [Tiberiou Seb]astos Kaisar: "of Tiberius Caesar Augustus."  The reverse bears the image of a Greco-Roman temple with the date of issue in Greek letters between the columns, surrounded by the off-center inscription (counter-clockwise) [Philippou T]etrarchou Ktis[tou]: "of Philip the Tetrarch, Founder."