After David became king over all Israel, he captured the Jebusite stronghold in Jerusalem. The biblical account identifies this stronghold as Zion and states that it became the City of David.
David brought the Ark of the Covenant into Jerusalem, and Solomon subsequently constructed the Temple north of the original City of David.
Over time the name Zion expanded beyond the original stronghold and became closely associated with the Temple, Jerusalem, and the dwelling place of God.
The Psalms celebrate Zion as the city of the great King, while the prophets use Zion extensively in messages of judgment, restoration, salvation, and future hope.