Judah the Prince
Judah the Prince (Hebrew: יהודה הנשיא, Yehudah HaNasi) or Judah I, also known as Rabbi or Rabbenu HaQadosh (Hebrew: רבנו הקדוש, "our Master, the holy one"), was a 2nd-century CE rabbi and chief redactor and editor of the Mishnah. He was a key leader of the Jewish community during the Roman occupation of Judea . According to the Talmud he was of the Davidic line, the royal line of King David, hence the title nasi, meaning prince. The title nasi was also used for presidents of the Sanhedrin. Judah died on 15 Kislev around 217 CE.
Judah the Prince was born in 135 CE. According to the Midrash, he came into the world on the same day that Rabbi Akiva died a martyr's death. The Talmud suggests that this was a result of Divine Providence: God had granted the Jewish people another leader of great stature to succeed Rabbi Akiva. His place of birth is unknown; nor is it recorded where his father, Shimon ben Gamliel II, sought refuge with his family during the persecutions under Hadrian. He is the only tanna known as Rabbeinu haQadosh, "our holy teacher" due to his deep piety.
Upon the restoration of order in the Land of Israel, Usha became the seat of the academy and Judah spent his youth there. His father presumably gave him the same education that he himself had received, including Greek language. This knowledge of Greek enabled him to become the Jews' intermediary with the Roman authorities. He favored Greek as the language of the country over Syriac (Aramaic). It is said that in Judah's house, only Hebrew was spoken, and even the maids spoke it.
"During Rabbi's career, not only did the scope of rabbinic jurisdiction increase, but the power of the central rabbinic office increased as well. In contrast with his predecessors, Rabbi assumed the responsibilities of a communal functionary by appointing and deposing local leaders and by checking the family purity of Jews in a distant locale. Similarly, he made unprecedented efforts to create a more popular halakhic system. In this vein, he permitted the use of produce immediately following the end of the sabbatical year, the import of produce into the Holy Land, and the acquisition of land from a sikarikon. Thus, while Rabbi strengthened his ties with the wealthy, he also broadened his power base by becoming a more popular figurehead."
According to the Talmud (Avodah Zarah 10a-b), Judah haNasi was very wealthy and greatly revered in Rome. He had a close friendship with "Antoninus", possibly the Emperor Antoninus Pius,  though it is more likely his famous friendship was with Emperor Marcus Aurelius Antoninus  who would consult Judah on various worldly and spiritual matters.
Compiler of the Mishna
According to Rabbinical Jewish tradition, God gave both the Written Law (Torah) and the Oral Law to Moses on Mount Sinai. The Oral Law is the oral tradition, as relayed by God to Moses and from him, transmitted and taught to the sages (rabbinic leaders) of each subsequent generation.
For centuries, the Torah appeared only as a written text transmitted in parallel with the oral tradition. Fearing that the oral traditions might be forgotten, Judah HaNasi undertook the mission of consolidating the various opinions into one body of law which became known as the Mishnah. This completed a project which had been mostly clarified and organized by his father and Rabbi Natan. 
The Mishnah consists of 63 tractates codifying Jewish law, which are the basis of the Talmud. According to Rabbi Abraham ben David, the Mishnah was compiled by Rabbi Judah the Prince in anno mundi 3,949, or what is also the year 500 of the Seleucid Era, which date corresponds to 189 CE.
Various stories are told about Judah haNasi to illustrate different aspects of his character. One of them begins by telling of a calf breaking free from being led to slaughter. According to the story, the calf tries to hide under Judah haNasi's robes, bellowing with terror, but he pushes the animal away, saying: "Go — for this purpose you were created." For this, Heaven inflicted upon him kidney stones, painful flatulence, and other gastric problems, saying, "Since he showed no pity, let us bring suffering upon him".
The story remarks that when Judah haNasi prayed for relief, the prayers were ignored, just as he had ignored the pleas of the calf. Later he prevented his maid from hurting the offspring of a mongoose, on the basis that "It is written: 'His Mercy is upon all his works.'" For this, Heaven removed the gastric problems from him, saying, "Since he has shown compassion, let us be compassionate with him".
Rabbi Judah HaNasi also said, "One who is ignorant of the Torah should not eat meat." This is because one who is ignorant is on the same level as animals. What, therefore, gives him the right to partake of them as food? Perhaps the punishment he received for lacking compassion towards the calf helped him to see that eating animals is not a matter that should be treated lightly.
While teaching Torah, Rabbi Judah would often interrupt the lesson to recite the Shema prayer. He passed his hand over his eyes as he said it. (Berachot 13b).
Before he died, Rabbeinu HaKadosh said: ‘I need my sons!... Let the lamp continue to burn in its usual place; let the table be set in its usual place; let the bed be made in its usual place.” (Ketubbot 103a)
Rabbi Judah said: "Much have I learned from my teachers, more from my colleagues, but most from my students." 
Sefer Chassidim Sec. 1129. (Cf. Kesubbos/Ketubot 103a.) records that after his death Rabbeinu HaKadosh used to visit his home, wearing Shabbos (Shabbat) clothes, every Friday evening at dusk. He would recite Kiddush, and others would thereby discharge their obligation to hear Kiddush. One Friday night there was a knock at the door. "Sorry," said the maid, "I can't let you in just now because Rabbeinu HaKadosh is in the middle of Kiddush." From then on Rabbeinu HaKadosh stopped coming, since he did not want his coming to become public knowledge.
- M. Avi-Yonah, The Jews of Palestine (English translation), (New York: 1976), p. 58.
^ Ephraim E. Urbach, The Sages (English translation), (Jerusalem: 1979), p. 599.
- Talmud Yerushalmi, quoted in Tosafot, Sanhedrin 5a.
- Mishna Chagiga 2:2.
- Judah Goldin, "The Period of the Talmud" in L. Finkelstein (ed.), The Jews: Their History (Schocken, New York: 1970), p. 172.
^ L. Margolis and A. Marx, A History of the Jewish People (Atheneum, New York: 1980), p. 225.
- Midrash Genesis Rabbah 53; Midrash Eccl. Rabbah 1:10.
- Mordechai Katz (2000). Understanding Judaism: a basic guide to Jewish faith, history, and practice. Mesorah Publications. p. 362. ISBN 978-1-57819-517-6. Retrieved 7 September 2011.
- Sotah 49b.
- Sotah 49b.
- Megillah 18a; Rosh Hashana 26b; Naz. 3a; 'Er. 53a.
- Amram Tropper, Wisdom, Politics, and Historiography: Tractate Avot in the Context of the Graeco-Roman Near East (Oxford: Oxford University Press, 2004), 130-131.
- A. Mischcon, Abodah Zara, p.10a Soncino, 1988. Mischcon cites various sources, "SJ Rappaport... is of the opinion that our Antoninus is Antoninus Pius." Other opinions cited suggest "Antoninus" was Caracalla, Lucius Verus or Alexander Severus.
- 'Codex Judaica' Kantor, second edition, NY 2006, page 146
- Babylonian Talmud (Talmud Bavli), Tractate Bava Metzia 85a, Tractate Pesachim 49b; Jerusalem Talmud, Tractate Kelaim 9, 32a-b.
- 'Codex Judaica' Kantor, second edition, NY 2006, page 146
- Abraham ben David, Seder Ha-Kabbalah Leharavad, Jerusalem 1971, p.16 (Hebrew)
- Leo Rosten, The Joys of Yiddish -ISBN 0-671-72813-X (1968), page 251.
Shimon ben Gamliel II
165 (Est.) - 220