I had no idea where the phrase 'Halcyon days' came from until I read this beautiful lyric by the ancient Greek poet Simonides:
'During the winter solstice
Zeus orders fourteen days of peaceful weather
and man has called this windless season holy
for then the mottled halcyon rears its young.'
A Halcyon was a kind of Kingfisher (probably - we're not even sure which colours the ancient Greeks were referring to in their literature; there is no ancient Greek word for 'blue'). They believed it nested on the open sea in midwinter, coinciding with two weeks of calm, mild weather.
The most celebrated Greek lyric poet is Sappho, none of whose work has survived intact. Often her manuscripts were torn into vertical strips: they were used as mummy-wrapping! So in many cases we only have incomplete lines, but sometimes when those fragments are presented together, they coalesce into something extraordinary:
your lovely face
if not, winter
and no pain
I bid you, Abanthis
take up the lyre
and sing of Gongyla as again desire
floats around you
the beautiful. when you saw her dress
it excited you. I'm happy.
The Kypros-born once