The answer to the question: “how long did the conquest of Canaan last” is found in Joshua 11:18; 14:7, 10, 11; 23:1; 24:29. Joshua 11:18 simply reads, “Joshua made war a long time with all those kings” and it doesn’t specify the period. And according to Joshua 14:7, 10, 11, Caleb was 40 years old when Moses sent him from Kadesh-barnea to explore the land of Canaan, and 45 years had passed since that time.
The conquest of the land was by this time considered complete, as Joshua 11:23 indicate. “So Joshua took the whole land, according to all that the LORD had said to Moses; and Joshua gave it as an inheritance to Israel according to their divisions by their tribes. Then the land rested from war” (Joshua 11:23; 14:5).
This does not mean that all the land was under the Israelite rule, for God had promised only a slow taking over Canaan so that the land doesn’t become a wilderness. “I will not drive them out from before you in one year, lest the land become desolate and the beasts of the field become too numerous for you. Little by little I will drive them out from before you, until you have increased, and you inherit the land” (Ex. 23:29, 30).
Since the mission of the spies took place on the second year of the Exodus (Deut. 2:14), and the sojourning in the wilderness lasted 38 years, the conquest lasted between 6 and 7 years (45–38 = 7).
Then, Joshua ruled for “a long time after the LORD had given rest to Israel from all their enemies round about, that Joshua was old, advanced in age” (Joshua 23:1). But how long was the period of his ruling is not given. And according to Joshua 24:29, Joshua was 110 years old when he died. So, Josephus (Antiquities v. 1. 29) divides Joshua’s life into three parts: 45 years before the Exodus, 40 years with Moses, and 25 years as sole leader.
In His service,