Kirjath-Sepher
Kirjath-sepher (UPDV: Kiriath-sepher) is the older name for the city more commonly called Debir, a town in the mountains of Judah. The city carries three names across the record — Kiriath-sepher, Kiriath-sannah, and Debir — with the older names preserved alongside the later one. It is best known as the city Othniel captures, winning Caleb's daughter Achsah, and it is later set apart as one of the Aaronite priestly cities.
The Older Name
The book of Joshua introduces the place with an explicit equation: "And he went up from there against the inhabitants of Debir: now the name of Debir formerly was Kiriath-sepher" (Josh 15:15). A separate notice in the same chapter records a third name: "and Dannah, and Kiriath-sannah (the same is Debir)" (Josh 15:49). The town's later identity (Debir) absorbs two earlier names, of which Kiriath-sepher is one.
Anakim at Debir
Before Caleb's challenge, the city is on the list of Anakim strongholds that Joshua clears: "And Joshua came at that time, and cut off the Anakim from the hill-country, from Hebron, from Debir, from Anab, and from all the hill-country of Judah, and from all the hill-country of Israel: Joshua completely destroyed them with their cities" (Josh 11:21). The Anakim are expelled in the broader hill-country campaign, of which Debir is one named site.
Caleb's Challenge and Othniel's Capture
The capture of Kiriath-sepher comes by Caleb's offer of his daughter to whoever can take it: "And Caleb said, He who strikes Kiriath-sepher, and takes it, to him I will give Achsah my daughter as wife. And Othniel the son of Kenaz, the brother of Caleb, took it: and he gave him Achsah his daughter as wife" (Josh 15:16-17). The Judges account preserves the same incident in nearly identical wording, again preserving the older name in parentheses: "And from there he went against the inhabitants of Debir. (Now the name of Debir formerly was Kiriath-sepher.) And Caleb said, He who strikes Kiriath-sepher, and takes it, to him I will give Achsah my daughter as wife. And Othniel the son of Kenaz, Caleb's younger brother, took it: and he gave him Achsah his daughter as wife" (Judg 1:11-13). The two accounts agree on the offer, the taker, and the marriage that follows.
A Levitical City
When the Levitical-city allotments are made, Debir is set apart with its surrounding pasture lands for the priestly Aaronites: "and Holon with its suburbs, and Debir with its suburbs" (Josh 21:15). The town that had been a Canaanite stronghold and a prize of the Othniel campaign becomes part of the network of priestly cities scattered through Judah.