title: Ricardo plc
context: Ricardo plc is a British publicly listed company named after its founder, Sir Harry Ricardo, originally incorporated and registered as Engine Patents Ltd. in 1915.  Since 1919 the headquarters have been at Shoreham-by-Sea, West Sussex.  Ricardo develops engines, transmissions, vehicle systems, intelligent transportation systems (ITS) and hybrid & electric systems.  The industries served are in transportation, defence and clean energy.
question: When was the company Ricardo plc founded?
answers: 1915