This is just one of hundreds of fascinating images on the Twitterfeed Of Things Past And Imagined (@VeraNijveld), a great discovery full of extraordinary and very beautiful material. The image is from a Carolingian manuscript in St. Emmeram’s Abbey (Kloster Sankt Emmeram or Reichsabtei Sankt Emmeram), now known as Schloss Thurn und Taxis. A moment (momentum) was a medieval unit of time. The movement of a shadow on a sundial covered 40 moments in a solar hour, a twelfth of the period between sunrise and sunset. The length of a solar hour depended on the length of the day, which, in turn, varied with the season. Although the length of a moment in modern seconds was therefore not fixed, on average a moment corresponded to 90 seconds. The hour was divided into four puncta (quarter-hours), ten minuta, or 40 momenta. The unit was used before the introduction of the mechanical clock and and the base 60 system in the late 13th century. The unit would not have been used in everyday life. For medieval commoners the main marker of the passage of time was the call to prayer at intervals throughout the day.The earliest reference found to the “moment” is in the 8th century writings of the Venerable Bede. By the 13th century the moment had been further subdivided into 12 “ounces”, each consisting of 47 “atoms”.