A time of happiness and prosperity. Halcyon is the Greek for a kingfisher, compounded of hals (the sea) and kuo (to brood on). The ancient Sicilians believed that the kingfisher laid its eggs and incubated for fourteen days, before the winter solstice, on the surface of the sea, during which time the waves of the sea were always unruffled.
Amidst our arms as quiet you shall be As halcyon brooding on a winter's sea.
The peaceful kingfishers are met together About the deck, and prophesie calm weather.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894