The Stronghold Olde English Faire (or simply Stronghold) occurs for one weekend, after the Bristol Renaissance Faire season ends, usually at the beginning of October at the Stronghold Retreat Center in Oregon, Illinois. In 2005, it ran the weekend of October 1-2.
Most performers there are (or were) also performers at Bristol. The environment is a lot more laxed at Stronghold (performers are allowed to break character, no scenario, etc.) as it is an independent Renaissance faire.