The inspiration for this song was the pain Sting felt from the failure of his first marriage. In a Musician magazine interview later that year, he said:"Fortress' is about appeasement, about trying to bridge the gaps between individuals. The central image is a minefield that you've laid around this other person to try and protect them. Then you realize that you have to walk back through it. I think it's one of the best choruses I've ever written."
The song was inspired by Sting's divorce.
The song was also released as a single, and reached #8 and #49 on the U.S. and U.K. singles charts, respectively.
The song reached #1 for two weeks on the Billboard Top Rock Tracks chart, becoming his second consecutive #1 hit on this chart.
During one of Sting's first performances of the song in concert in Paris, his crew lowered a tiny fortress onto the stage in a parody of the similar Stonehenge scene from the film This Is Spinal Tap.