Ai - "Heap of Ruins" - refers to two places in ancient Israel (See History of ancient Israel and Judah)

1. A royal city in Canaan, the second one taken by the Israelites.

It is mentioned in Abraham's time; he is said to have pitched his tent with Bethel on the west and Ai at the east. (Ge. 12:8) He built an altar there and visited the place again after being in Egypt.

In Joshua's time, Ai was attacked by a small force of about 3000 soldiers, but they suffered defeat because of the sin of Achan. (Jos. 7:4-15) After correction of this matter, Joshua employed a strategy against the city, setting an ambush at the rear of the city on the west side. The city was captured and set on fire. It was razed to the ground. (Jos. 8:1-28)

It is mentioned as an inhabited place during Isaiah's time, and was said to be the first place to be taken by Assyria at the march on Jerusalem. (Isa. 10:28) After the Babylonian exile, people from Ai returned with Zerubabel's caravan. (Ez. 2:28)

Ai is popularly identified with Et-Tell southeast of Bethel. However, the recent work of Dr. Bryant Wood sheds serious doubt on this location.

2. A city mentioned along with Heshbon in Jeremiah 49:3. Its location is unknown.

de:Ai (Historischer Stadtstaat)