The Monosoupape (French for single-valve), was a rotary engine design first introduced in 1913 by Gnome Engine Company (renamed Gnome et Rhône in 1915). It used a clever arrangement of internal transfer ports and a single pushrod-operated exhaust valve to replace the many moving parts found on more conventional rotary engines, and made the "Monosoupape" engines some of the most reliable of the era. British aircraft designer Thomas Sopwith described the "Monosoupape" as "one of the greatest single advances in aviation".