Complex sentence: Fort Albany was a bastioned earthwork built by the Union Army in Arlington County (then still known as Alexandria County) in the U.S. state of Virginia in 1861 as part of the defense of Washington during the American Civil War.
Split into simpler sentences: Fort Albany was a bastioned earthwork built by the Union Army in Arlington County (then still known as Alexandria County) in the U.S. state of Virginia. It was built in 1861 as part of the defense of Washington during the American Civil War.