After the defeat of General Edward Braddock at the Battle of the Monongahela (9 July 1755), the white settlers of the Allegheny Mountains were largely unprotected from a series of Shawnee and Delaware Indian raids. By the end of the year, the Virginia Regiment had increased its numbers by several hundred troops and began to temporarily man some of the settler forts that had been hastily thrown up by civilians or soldiers. Fort Seybert was built on the South Fork of the South Branch of the Potomac River within about 100 yards of a pre-existing structure known as John Patton's Mill. Patton had owned the land since 1747, but sold it in 1755 to Jacob Seybert.