Sentence:  The huge square box, parquet-floored and high-ceilinged, had been arranged to display a suite of bedroom furniture designed and made in the <WSD>halcyon</WSD> days of the last quarter of the nineteenth century, when modish taste was just due to go clean out of fashion for the best part of the next hundred years. 
Meaning of the word marked with <WSD> tags:  Calm, undisturbed, peaceful, serene.