Saul was [forty] years old when he began to reign; and when he had reigned two years over Israel,
Only a few writers have expressed confidence in what is meant.  Adam Clarke, for example, stated that, "The first clause in  1 Samuel 13:1 belongs to the preceding chapter and carries the meaning that what is related there took place in the first year of Saul's reign; and that the second clause means that the events of  1 Samuel 13 took place in the second year of his reign.[2]  This appears to be an improbable solution.