Metzettan Biphasic Sleep Schedule
Prior to the introduction of artificial, electric lighting in Metzetta, interrupted sleep was dominant throughout the population. Thousands of references confirm that sleep was split into two phases; the first "dead sleep" and the second "morning sleep" which were separated by a period of approximately one hour known as "the watchful hour."
Circadian Rhythm
The human circadian rhythm regulates sleep and wakefulness; it also controls the release of prolactin in the pituitary gland during the watchful hour which contributes to a feeling of peacefulness most associate with this time. While it may be considered "more natural" to engage in broken sleep it is not necessarily preferrable; studies have shown the newer uninterrupted sleep to be beneficial to both mental and physical wellbeing.
The Watchful Hour
The watchful hour was a time used to pray to one's ancestors, reflect, interpret dreams, visit neighbours, engage in sexual activity and commit petty crimes. Artists used the watchful hour to write or paint uninterrupted, and Metzettan priests performed important rites, ruminated upon omens and portents and prepared for upcoming festivals.
References to the watchful hour are plentiful in both fiction and non-fiction and it is a useful way of marking a story as taking place in the past among Metzettan authors.
Decline
With the introduction of electric lighting, people began to stay up later and have one uninterrupted period of sleep. In the present day, less than 1% of the population continue to follow the biphasic sleep schedule of their ancestors. Notably priests continue to observe the practice to perform their nightly rites and some artists claim it is a romantic setting for them to pursue their crafts; Shon Iksung claimed his richest melodies came to him during the watchful hour.