Probably around 2003 when I first heard Juno Reactor's downtempo stuff. Around the same time I was listening to a lot of stuff that could be considered the ancestors of "modern" psybient - The Orb, FSOL, Banco De Gaia etc. A couple of years later I heard Shpongle for the first time, which was when I first became aware that psy-chill was a fully fledged scene rather than a few weird tracks to be found on psy albums.