[Hot Tabasco]

an island south of Mosul in the Tigris River believed to be a safe haven

Unless you have a lot of boats, the only way on and off an island is via a bridge.......Not sure I would use it as a "safe haven".......

[Mr. Lucky]

In the 7th century, concentrating all of your strength on a small river island may, or may not, have been a good idea. In the 21st century, against an opponent with overwhelming air power, not so much.