The intellectual and academic phenomenon known as, "Philhellenism", is a Modern European and American fascination, appreciation and "love" for the culture and civilization of Ancient/Classical Greece-(typically from Homer, until Cleopatra). The Archaeological discipline and field essentially grew out of a European and American fascination with the distant origins of the West, in particular, with the Ancient Greek West. The fields of Classics, Ancient Philology, the study of Ancient Western languages and Literature, as well as the birth of the Modern Museum, were, to a great extent, rooted in the love and appreciation for Ancient civilizations, in particular, Ancient Greek civilization; (the very word, "Museum", derives from the Ancient Greek word, "Muse").
However, one can find examples of Ancient Philhellenism, beginning with King Philip of Macedon and his famous son, Alexander. Both Philip and Alexander were Greco-Macedonians, however, King Philip transformed the semi-primitive Greco-Macedonian culture into more of a Greco-Athenian or Greco-Peloponnesian culture. King Philip changed the centuries old Greco-Macedonian language and introduced the Athenian style of Greek into greater Greco-Macedonian society. Of course his son, Alexander The Great, though a Greek himself, was arguably, the greatest Philhellene of all time. Alexander's empire spread from Northern Greece, to the Northern Indian subcontinent-(present-day Pakistan). His short lived, but vast empire, helped to usher in a new, "Hellenistic Age"-(a Greek Imperial age which emphasized the utilization of the Greek language and affiliation with the larger Greek culture).
In the case of well known ancient Philhellenes who were not of ethnic Greek descent, there are 5 major figures that, from my perspective, who were also, some of the greatest Ancient and Early Medieval Philhellenes in History; Saints Andrew, Paul and Athanasius, as well as Emperor Constantine and his Mother, Helena.
Andrew, was the brother of Simon-(Saint Peter). Both Andrew and Simon were originally of the Jewish faith and were natives of the Galilee in Northern Israel-(specifically, from the town of Capernaum). Although Simon-Peter is the Founder of the Roman Catholic Church, less is known about his brother, Andrew. Simon-Peter may or may not have known the Greek language, though his brother, was articulate in the Greek language and like many of Jesus' original apostles/disciples, Andrew traveled to the pagan land of Greece to preach the Christian message. In the case of Andrew, he spent his final years in Patras, Greece-(about 100 miles West of Athens and 100 miles North of Olympia) preaching to the largely Greek pagan audience. He was subsequently arrested, tortured and executed by the Roman Colonial Authorities in Patras. The famous "Cross of Saint Andrew"-(which represents his martyrdom), was said to have occurred in Patras and the most sacred Church within Greece proper-(which contains an encased portion of the Original X shaped Cross), is built on this historic site. Andrew-(known as Saint Andrew by the Christians), is the Founder of the Greek Orthodox Church and is widely viewed by the Greek Orthodox Church and population, to be one of the most important Philhellenes in History. Every Greek Orthodox Patriarch, to the present-day, is the heir to the legacy of Saint Andrew-(just as every Pope, to the present-day, is the heir to the legacy of his brother Simon-Peter......Saint Peter).
Saul of Tarsus, then Paul of Tarsus, was also one of the most significant Philhellenes in History. Saul/Paul was from the Asia Minor Town of Tarsus-(in close proximity to Northern Syria). Although a Tent Maker by Trade, Saul/Paul was a Roman citizen, who was impressively multilingual. He was probably literate in 5 languages, Greek, Latin, Aramaic, Hebrew and Syriac. Although Saul/Paul was born and raised in a pagan town, he was righteously devoted to his Jewish faith and a member of the Pharisees subculture. For many years, Saul/Paul was notorious for having persecuted both Jewish and pagan converts to Christianity. After his (alleged) divine experience in Syria-(his famous, "Road to Damascus" conversion), Saul became Paul and then would become the greatest Christian proselytizer and first international Missionary with most of his time spent in the larger Greek speaking world.
One has to remember that when reading the majority of Paul's letters.....these were letters that were addressed to the first Christians who resided in Greek cities-(under Roman colonial occupation), such as, Ephesus, Philippi, Corinth and Thessaloniki, as well as the larger region of Galatia in Asia Minor. Paul gave his famous speech before the Greco-Athenian Supreme Court and along with his friend Barnabas, had begun his international missionary work in Cyprus. Saint Paul also traveled to Crete, the Northern Greek cities of Kavalla-(originally known as Neapolis) and Veria, (as well as to the famed city of Troas, which was the rebuilt city of Troy). In other words, much of Saint Paul's original early missionary work consisted of his travels and interactions-(both verbal and written) with Greek peoples-(of all ranks and classes). Although Paul's knowledge of the Greek language was more conversational and less formal in tone and expression, it had a significant impact on the larger Greek society. Some Greeks dismissed Paul as a crazed preacher, while others were convinced of his missionary message. Paul may or may not have loved the Greeks, though his missionary messaging was primarily directed at a Greek audience, thereby making him one of the most important and consequential Philhellenes in History.
In the case of Saint Athanasius-(as well as Helena and Constantine),they were not Philhellenes of the classical type, rather, they were the earliest of Early Medieval Greco-Byzantine Philhellenes. Saint Athanasius, a beloved Saint within the Greek Orthodox Church, was actually of Egyptian descent, though articulate and well versed in the Greek language. Athanasius, was the Prime Defender of Trinitarian Christianity and was a vocal presence at the Nicene Council. Athanasius' Christianity, was essentially a Greco-Egyptian Christianity...a Christianity of the Eastern rite and was very central to the development of Egyptian and particularly, Greek theological identity; a true Greco-Byzantine Philhellene.
Both Helena and Constantine were Roman. Although Constantine was the one who initially built an Ecclesiastical institution over the Tomb of Saint Peter in Rome, (what would become Saint Peter's Basilica 1300 years later), Constantine, was very much a Philhellene. He spoke and communicated in the Greek language-(though not fluently), claimed to have had a vision of the Cross with the famed Chi Ro letters-(at least when interpreted from a Greek perspective), ordered the Chi Ro letters to be inscribed into the shields of his soldiers and Generals and chose to relocate the Roman Empire to 2 other cities; the Northern Italian City of Milan and the Ancient Greek city of Byzantium, which he would rename on his behalf. Constantine's relocation to Byzantium was probably more geopolitically strategic than rooted in Philhellensim. Nevertheless, such a strategic move would essentially rejuvenate Greek imperial power-(which had been suppressed for centuries under Roman colonial rule).
Constantine's Mother, Helena, was more of a cultural Philhellene. Helena had spent a good deal of time in Israel/Palestine. It was Helena-(and Constantine) who commissioned the Original Church of the Holy Sepulcher in Jerusalem which was and is still largely, an Eastern rite, predominantly Greek speaking Church-(the most sacred in all of Christendom). Helena was also said to have recovered sizable portions of the Jesus Cross. She traveled to island of Cyprus and helped found a religious order which preserves-(or is alleged to preserve), portions of the Jesus Cross to this day-(unfortunately, I don't remember the name of the Greco-Cypriot Monastery). Helena then traveled to the Greco-Aegean island of Paros and commissioned the building of Greece's 2nd oldest Church-(Known as The Church of the 99 Doors. Much of its original interior structure exists to this day). In other words, Helena, was, in a way, the first Philhellenic Archaeologist.
So as you can see, there is a fairly long history of Philhellenism and Philhellenes, of which five figures have been highlighted. There are many other Ancient, as well as Early Medieval Philhellenes, though such descriptions would be much too detailed for a single posting.