2 Maccabees 4:13
11 He set aside the existing royal concessions to the Jews, secured through John the father of Eupolemus, who went on the mission to establish friendship and alliance with the Romans; and he destroyed the lawful ways of living and introduced new customs contrary to the law. 12 He took delight in establishing a gymnasium right under the citadel, and he induced the noblest of the young men to wear the Greek hat. 13 There was such an extreme of Hellenization and increase in the adoption of foreign ways because of the surpassing wickedness of Jason, who was ungodly and no true high priest, 14 that the priests were no longer intent upon their service at the altar. Despising the sanctuary and neglecting the sacrifices, they hurried to take part in the unlawful proceedings in the wrestling arena after the signal for the discus-throwing, 15 disdaining the honors prized by their ancestors and putting the highest value upon Greek forms of prestige.
Josephus Antiquities of the Jews Book 12 5:1
1 About this time, upon the death of Onias the High Priest, they gave the High Priesthood to Jesus his brother: for that son which Onias left was yet but an infant. And in its proper place we will inform the reader of all the circumstances that befel this child. But this Jesus, who was the brother of Onias, was deprived of the High Priesthood by the King, who was angry with him, and gave it to his younger brother; whose name also was Onias. For Simon had these three sons; to each of which the High Priesthood came: as we have already informed the reader. This Jesus changed his name to Jason; but Onias was called Menelaus. Now as the former High Priest, Jesus, raised a sedition against Menelaus, who was ordained after him, the multitude were divided between them both. And the sons of Tobias took the part of Menelaus: but the greater part of the people assisted Jason; and by that means Menelaus, and the sons of Tobias were distressed, and retired to Antiochus, and informed him, that they were desirous to leave the laws of their countrey, and the Jewish way of living according to them; and to follow the King’s laws, and the Grecian way of living. Wherefore they desired his permission to build them a Gymnasium at Jerusalem. And when he had given them leave, they also hid the circumcision of their genitals; that even when they were naked they might appear to be Greeks. Accordingly they left off all the customs that belonged to their own countrey, and imitated the practices of the other nations.
Notes and References
"... A “reform” was attempted which took on various dimensions. Just before 175 BCE there was a split in the Judean aristocracy, that is, between the Zadokite high priest Onias III and his brother Jason. The latter was in favour of Hellenization, or more specifically, the adoption of Greek education, athletics and dress. The attempt was further made to transform Jerusalem into a Greek polis, or at least, for the citizens to be called “Antiochenes”. Jason, the “ungodly wretch, and no high priest” (2 Maccabees 4:13) was appointed and had support from Antiochus IV Epiphanes (“God revealed”) who came to power in Syria in 175. 1 Maccabees describes that there were “wicked men” in Israel who wanted to make a covenant with the [Gentiles or nations], and who was granted permission by the king to observe Gentile ordinances (1 Maccabees 1:11-13). Having obtained permission, they returned to Jerusalem where they built a gymnasium at the foot of the Temple. According to 2 Maccabees 4:9 Jason also asked for a training centre to be built. In this manner a process was initiated whereby the Hellenistic spirit could be instilled in young Judean men. It is claimed that Antiochus further encouraged young Judean men to reject the ancestral law: “Share in the Greek style, change your mode of living, and enjoy your youth” ..."
Cromhout, Markus A Clash of Symbolic Universes: Judeanism vs Hellenism (pp. 1089-1117) HTS Teologiese Studies / Theological Studies 63(3), 2009