"The halcyon is a sea bird that nests by the shore, laying its eggs in the sand, and bringing forth its young in the middle of winter when the sea beats against the land in violent and frequent storms. But during the seven days while the halcyon broods — for it takes but seven days to hatch its young — all winds sink to rest, and the sea grows calm.... Since all sailors know of this, they give this time the name of the halcyon days."
 
Given the state of science in the fourth century, A.D., no doubt St. Basil the Great and his contemporaries firmly believed what he wrote about this mythical bird.  Others thought the halcyon's nest floated in the seas,  during the days of the winter solstice and the bird had the power of charming winds and waves into calmness.

Now science identifies the bird as the halcyon coromanda, the Ruddy Kingfisher, with no special powers.

And yet, sailors knew of winter's improbable calm days.

As people today sail through the sometimes stressful Thanksgiving, Ramadan, Hanukkah, Christmas, Kwanzaa, New Year's Eve and Day, Epiphany, Chinese New Year holiday period,
may all find some halcyon days of peace.