What are the three jewish diasporas and when did they happen?

The Jewish state comes to an end in 70 AD, when the Romans begin to actively drive Jews from the home they had lived in for over a millennium. But the Jewish Diaspora ("diaspora" ="dispersion, scattering") had begun long before the Romans had even dreamed of Judaea. When the Assyrians conquered Israel in 722, the Hebrew inhabitants were scattered all over the Middle East; these early victims of the dispersion disappeared utterly from the pages of history. However, when Nebuchadnezzar deported the Judaeans in 597 and 586 BC, he allowed them to remain in a unified community in Babylon. Another group of Judaeans fled to Egypt, where they settled in the Nile delta. So from 597 onwards, there were three distinct groups of Hebrews: a group in Babylon and other parts of the Middle East, a group in Judaea, and another group in Egypt. Thus, 597 is considered the beginning date of the Jewish Diaspora. While Cyrus the Persian allowed the Judaeans to return to their homeland in 538 BC, most chose to remain in Babylon. A large number of Jews in Egypt became mercenaries in Upper Egypt on an island called the Elephantine. All of these Jews retained their religion, identity, and social customs; both under the Persians and the Greeks, they were allowed to run their lives under their own laws. Some converted to other religions; still others combined the Yahweh cult with local cults; but the majority clung to the Hebraic religion and its new-found core document, the Torah.In 63 BC, Judaea became a protectorate of Rome. Coming under the administration of a governor, Judaea was allowed a king; the governor's business was to regulate trade and maximize tax revenue. While the Jews despised the Greeks, the Romans were a nightmare. Governorships were bought at high prices; the governors would attempt to squeeze as much revenue as possible from their regions and pocket as much as they could. Even with a Jewish king, the Judaeans revolted in 70 AD, a desperate revolt that ended tragically. In 73 AD, the last of the revolutionaries were holed up in a mountain fort called Masada; the Romans had besieged the fort for two years, and the 1,000 men, women, and children inside were beginning to starve. In desperation, the Jewish revolutionaries killed themselves rather than surrender to the Romans. The Romans then destroyed Jerusalem, annexed Judaea as a Roman province, and systematically drove the Jews from Palestine. After 73 AD, Hebrew history would only be the history of the Diaspora as the Jews and their world view spread over Africa, Asia, and Europe.