What was King David and most important achievement?

King David, a central figure in the Hebrew Bible, is best known for uniting the tribes of Israel and establishing Jerusalem as the nation’s capital. His most significant achievement was the consolidation of the Israelite kingdom, transforming it into a powerful and unified state. Additionally, David is credited with bringing the Ark of the Covenant to Jerusalem, which solidified the city’s religious significance. His legacy also includes a rich cultural impact, particularly through the Psalms, attributed to him.