In the Author's Note, O'Brian says that the USS Norfolk is a reference to the historical expedition of the USS Essex. Essex sailed in South Atlantic waters and along the coast of Brazil until January 1813 when Captain David Porter undertook commerce raiding against British whaling fisheries in the Pacific. Although her voyage was hampered from a shortage of provisions and heavy gales while rounding Cape Horn, she anchored safely at Valparaíso, Chile, on 14 March, having seized schooners Elizabeth and Nereyda along the way. The next five months brought Essex 13 prizes.