King Solomon built a magnificent Temple, dedicated to God, in Jerusalem. It was paneled in cedar wood imported from Lebanon and required the efforts of tens of thousands of workers to complete. It consisted of three rooms: an entryway; an oblong room containing the menorah, incensealtar, and table of twelves loaves of bread; and an inner sanctum, called the Holy of Holies, which contained the Ark of the Covenant in which, according to tradition, the Torah brought down Mount Sinai by Moses was kept. A detailed description of the Temple can be found in First Kings, chapter 6, in the Bible. The Temple was under the jurisdiction of the High Priest, descended from Aaron, the brother of Moses, and priests descended from the tribe of Levi ministered there daily, making the sacrifices commanded in the Torah and seeing to the maintenance of the Temple area. The sacrifices were Israel's link to God, a fulfillment of the covenant made with God at Mount Sinai.
In 586 B.C.E., the Temple built by King Solomon, stood in ruins. The Babylonians, under the rule of King Nebuchadnezzar, attacked the kingdom of Judah, destroying the Temple and Jerusalem on the ninth of Av in 586 B.C.E. Thousands of people were killed in the war, and of those who survived, the vast majority of the priesthood, nobility, and artisan classes were forcibly taken into Exile in Babylonia. Nebuchadnezzar left only farmers, shepherds, and some villagers in Judah, for without leadership, rebellion would be unlikely.
What happened to the Jewish people in Exile in Babylonia? We know that Exile lasted for 70 years, until Babylonia was conquered by the Persian Empire under King Cyrus, who gave the Jews permission to return to their land and rebuild their central sanctuary. During those 70 years in Babylonia, Jews settled and built homes, started businesses and raised families. They faced an unprecedented religious crisis: Exiled from their homeland and unable to offer sacrifices to God, since offering could only be made in the central sanctuary in Jerusalem, the Jews in Babylonia wrestled with whether their covenant with God was still operative. The prophet Ezekiel, who had preached before the Destruction and who had gone into Exile with them, assured them the covenant was eternal, and that God would some day return them to their Land. He shared with them a vision of valley of dry bones which God would bring back to life, covered with muscles, sinews, and flesh, a divine sign that the nation Israel would one day be resurrected from exile to live again as a nation in her own Land. In the meantime, to preserve their traditions, it seems that the Jews in Babylonia gathered together on market days (Mondays and Thursdays) and participated in some combination of worship and study. Some scholars believe that these gatherings gave rise to worship services, and that prayers were composed for use at this time which were eventually brought back to the Land of Israel when some of the Exiles returned, and incorporated into the cult worship when the Second Temple was eventually built.
Most of the Jews in Babylonia, however, remained there even after King Cyrus permitted them to return to the Land of Israel. By then, most Jews had been born in Babylonia; some were even the children of Jews born in Babylonia. They had built homes, businesses, and lives in Babylonia. While sacrifices could be offered only from the altar in Jerusalem, prayers could be offered anywhere. The focal point was still Jerusalem, however, as we know from Daniel's prayer -- he faces Jerusalem when praying to God. In time, schools of study grew in Babylonia, especially in the aftermath of the Destruction of the Second Temple by the Romans in 69 C.E., where prayer and study were full-time activities for the learned class. By the first century, synagogues emerge as the central institution of Jewish life once the Temple is destroyed, a place where study, worship, meeting, celebration, and civic meetings take place. There were synagogues not only in Babylonia, but in Alexandria and throughout the Land of Israel, in places such as Dora, Caesarea, Nazareth and Capernaum (the last four are mentioned by Josephus). The Talmud tells us that, at the time of the Destruction of the Second Temple, there were 394 synagogues in Jerusalem alone.
Once the Temple no longer stood, however, the worship service in the synagogue came to be a substitute for the sacrificial cult, an alternative means of serving God. Thrice daily services were instituted, with Shacharit, Minchah, and Ma'ariv featuring a long prayer called the Amidah (also called Ha-Tefilah -- "the Prayer" -- or Shemonah Esrei -- "the 18 benedictions).
In its essence and most import function, however, the synagogue was a Beit Midrash, a House of Study. Here, scholars and students would gather to study the sacred texts of Jewish tradition, interpreting their meaning for each new generation, and applying these interpretations toward the aim of living in covenant with God and improving the world in which they lived. It is important to point out that throughout Jewish history, the vast majority of synagogues have been simple, unprepossessing structures. The synagogue, itself, is not what was considered important nor worthy of lavishing time and resources upon; rather, what made the synagogue a holy place was the fact that it contained an ark in which a Sefer Torah resided. Moreover, it was the activities which took place there -- chiefly study and prayer -- which marked the place as important. Thus while other cultures built great monuments as expressions of their vision of God, most synagogues were small, modest buildings, barely discernible as houses of worship from the outside. In many communities, the "synagogue" might be no more than the bottom floor of a rabbi's house. In others, a simple wooden structure sufficed. In large cities, with abundant Jewish populations, larger structures were needed, and when the community had the resources, sometimes large, majestic structures were built. Florence, for example, is renowned for her synagogues.
Synagogues have, for over two millennium, served as the locus for Jewish life. They have combined the functions of House of Worship, House of Study, with those of philanthropy, social services, socializing, and community gathering place. Even in the darkest times, in the ghettos during World War II, and in Concentration Camps during the Holocaust, Jews have established synagogues to enable Jews to come together for prayer and study, that they might keep God's eternal covenant with Israel.