The "United Monarchy" refers to the period in ancient Israel when the twelve tribes were united under a single monarchy. This era is primarily associated with three kings: Saul, David, and Solomon. It is believed to have occurred around 1020 to 930 BCE, marking a significant transition from tribal confederation to centralized governance. During the United Monarchy, the capital was established in Jerusalem, which became a political and religious center. David is credited with unifying the tribes and expanding the kingdom, while Solomon is known for his wisdom and the construction of the First Temple, which solidified the city's importance in Jewish history.