Charles Ellicott Commentary Judges 9:51

"But there was a strong tower within the city, and thither fled all the men and women, and all they of the city, and shut themselves in, and gat them up to the roof of the tower." — Judges 9:51 (ASV)

There was a strong tower within the city. —This constant mention of towers and strongholds (Judges 8:9, etc.) shows the disturbed state of the country, which probably resembled the state of England in the days of King Stephen.

To the top of the tower. —“Standing about the battlements upon the roof of the tower” (Vulgate).