Campus Martius was a defensive fortification at the Marietta, Ohio settlement, and was home to Rufus Putnam, Benjamin Tupper, Arthur St. Clair, and other pioneers from the Ohio Company of Associates during the Northwest Indian War. Major Anselm Tupper was commander of the Campus Martius during the war. Construction began in 1788 and was fully completed in 1791. The Campus Martius was located on the east side of the Muskingum River, and upriver from its confluence with the Ohio River.