Interesting post, Clio. As Warwick says, Crete is on the Nightingales' migration route, so it's entirely possible that is what you have been hearing. It could be a Blackbird, as Bob says, as they sing after dark. A Nightjar is also possible, although I wouldn't describe their call as lovely and trilling. Haunting, certainly, but more a staccato and rather mechanical sounding "trrrrrrrr trrrrrrrr" building to a crescendo (if you see what I mean -- doesn't translate to words very well.) There is another possibility (although the time of day makes it unlikely if, as I assume, you do your ablutions after dark!) and that is Bee Eaters. They produce a gorgeous tinkling melody and we often hear them in the early evening flying up the gorge below our house. Delightful little birds, but I don't think they sing after dark, so I'd guess it is a nightingale singing you to sleep.