The Ilya Muromets () refers to a class of Russian pre-World War I large four-engine commercial airliners and heavy military bombing aircraft used during World War I by the Russian Empire. The aircraft series was named after Ilya Muromets, a hero from Russian mythology. The series was based on the Russky Vityaz or Le Grand, the world's first four-engined aircraft, designed by Igor Sikorsky. The Ilya Muromets aircraft as it appeared in 1913 was a revolutionary design, intended for commercial service with its spacious fuselage incorporating a passenger saloon and washroom on board. During World War I, it became the first four-engine bomber to equip a dedicated strategic bombing unit. This heavy bomber was unrivaled in the early stages of the war, as the Central Powers had no aircraft capable