When was the book of Samuel written?

The book of Samuel which is divided into two books in Christian bibles for convenience but they are actually one book. When the Masoretic texts were compared with Septuagint, it paints a strange picture of some effort made by some scribes who wants to portray the book of Samuel as historically old by removing all historical references for events after king David in Masoretic. It could also mean that the scribes of Septuagint want to add more information they know but Septuagint is older than Masoretic texts. We are not sure why these differences exists.

Masoretic Septuagint (LXX)
Birth of Solomon

2 Sam 5:14 Now these are the names of those who were born to him in Jerusalem: Shammua, Shobab, Nathan, Solomon,

No change

2 Sam 5:14 And these are the names of those that were born to him in Jerusalem; Sammus, and Sobab, and Nathan, and Solomon.

Solomon’s later activity removed

2 Sam 8:7-8 And David took the shields of gold that had belonged to the servants of Hadadezer, and brought them to Jerusalem. Also from Betah and from Berothai, cities of Hadadezer, King David took a large amount of bronze.

Written after Roboam began to reign (after 992 BC)

2 Sam 8:7-8 And David took the golden bracelets which were on the servants of Adraazar king of Suba, and brought them to Jerusalem. And Susakim king of Egypt took them, when he went up to Jerusalem in the days of Roboam son of Solomon. And king David took from Metebac, and from the choice cities of Adraazar, very much brass: with that Solomon made the brazen sea, and the pillars, and the lavers, and all the furniture.

Birth of Solomon

2 Sam 12:24 And David comforted Bersabee his wife, and he went in to her, and lay with her; and she conceived and bore a son, and he called his named Solomon, and the Lord loved him.

No change

2 Sam 12:24 And David comforted Bersabee his wife, and he went in to her, and lay with her; and she conceived and bore a son, and he called his named Solomon, and the Lord loved him.

Solomon’s later descendants removed

2 Sam 14:27 To Absalom were born three sons, and one daughter whose name was Tamar. She was a woman of beautiful appearance.

Written after Abia was born

2 Sam 14:27 And there were born to Abessalom three sons and one daughter, and her name was Themar: she was a very beautiful woman, and she becomes the wife of Roboam son of Solomon, and she bears to him Abia.

Solomon’s later activity removed

2 Sam 24:25 And David built there an altar to the LORD, and offered burnt offerings and peace offerings. So the LORD heeded the prayers for the land, and the plague was withdrawn from Israel.

Written after Solomon’s reign

2 Sam 24:25 And David built there an altar to the Lord, and offered up whole-burnt-offerings and peace-offerings: and Solomon made an addition to the altar afterwards, for it was little at first. And the Lord hearkened to the land, and the plague was stayed from Israel.

Based on the information we have from Septuagint, we can confidentially say that the book of Samuel was written after Rehoboam (or Roboam) began to reign 992 BC.