When was the Celtic festival Lughnasadh held?

The Celts had four major festivals,one of them being Lughnasadh,which was held on 1 August.It was the equivalent of the Christian harvest festival,so called because it was the… feast of the god Lugh.Later it became the christian festival of Lammas..now harvest festival.The three other festivals of the Celts were Samhain,Imbolc and Beltane. (MORE)