Midway through The Hour of Parade, I rather mysteriously mention that Anne-Marie was, at a certain point, “well into her first sleep” when a significant event began, and I suppose I’ve wondered what readers made of this. I learned in researching the book that prior to 1800 or so, sleep for many in Western Europe and, to a lessor extent, North America, was profoundly different than in our modern times, regulated as we are by alarms, sleep aids and artificial illumination.
In early modern times, people would wake midway through the night, get up to use the chamberpot, smoke, even visit their neighbors for a quiet chat. Others would wake but remain in bed where they’d make love, pray, and/or reflect on the dreams they’d just awoken from, which were, as a result, more vivid. Europeans of those times attached great significance to dreams for their power to explain the past and predict the future. Then, these activities complete, they'd enter what was called "second sleep."
Modern sleep research has shown that people deprived of artificial light at night fall into a similar pattern of sleeping in segments. There is historical evidence that once people began using candles and streetlamps, they slept in one, uninterrupted stretch.
In The Hour of Parade, I tried to show this for Anne-Marie, who, unlike the other characters, was used to living on a farm where people were still often experiencing segmented sleep.
An interesting book about this is Evening’s Empire A History of the Night in Early Modern Europe by Craig Koslofsky