Advice books are nothing new. Here’s an example from late Medieval Europe:
“Those who have weak stomachs should sleep face down, for it will aid digestion and will not allow phlegm to accumulate through the increase of natural heat which stiffens the harmful humors. Moreover, it is extremely helpful to sleep at first on the right side, then on the left. No one on their right mind should sleep lying on their back.”
– Bartolomeo Platina, De honesta voluptate et valetudine (c. 1474)
(Translation by Erik Jensen)
This rather strongly worded hint is found in a Latin-language cookbook De honesta voluptate et valetudine by Bartolomeo Sacci (1421-1481; better known as Platina). Platina’s work was published c. 1474, and is often called the world’s oldest printed cookbook. It’s more than a collection of recipes, however; it also included his reflections on health, healthy habits, and physical activity, for instance.
A scanned version in Latin (with full record) is available through the Rare Book and Special Collections Division of the Library of Congress.
As a side-sleeper, I (very non-seriously!) agree that sleeping on your back can’t be good for you. All of those wicked humors must then be free to wander around your body, you know… 😉
Image: Lancelot-Grail (The Prose Vulgate Cycle), Lancelot sleeping in a pavilion having killed the owner who lies outside, screencap of Add MS 10293, folio 283r via British Library (northern France; early 14th c.; illustration on parchment)
Some things are just too silly not to share!