In 2015, Airbus Helicopters unveiled the secrecy around its Dauphin successor and presented the all new H160 helicopter. A special feature immediately attracting attention is its unusual and revolutionary fore-aft swept main rotor blade. This design, aiming at significantly reducing the so-called blade-vortex interaction noise signature and also reducing fast forward flight power requirements, finds its origins far back in the 1990s. At that time DLR and ONERA formed a joint team to acoustically optimize a rectangular reference rotor blade. Based on state-of-the-art comprehensive rotor codes and a 50-50 work share, the ERATO rotor blade design was developed, patented worldwide and tested on a rotor test rig and in both wind tunnels, DNW-LLF in the Netherlands and S1 in France. Airbus Helicopters (then: Eurocopter) took up that design, optimized hover and forward flight high lift performance and prepared it for serial production, until it finally made it as the Blue EdgeTM rotor blade on the Airbus Helicopters H160 helicopter. The presentation covers the motivation for noise reduction, the history of the ERATO/Blue EdgeTM rotor blades and technical achievements, wind tunnel test results and flight tests