Some Latin Measures

This is more for me than for any other reason but as long as I’m making a crib sheet, I might as well post it in case it is useful for someone else. I will add to this as needed.

Hectare -- a modern measure of area, equal to 2.471 acres or 107,639 sq. ft.

Roman Modius -- a measure of volume, often used to measure grain. I will use 8.73 liters as the size of this unit. It is interesting to note that it is often translated as “about two gallons”.

• The Roman Modius is equal to 8.736 liters according to http://www.livius.org/w/weights/weights2.html
• It is given as 8.75 liters in Agricultural Implements and Farm Equipment in the Roman World, by K. D. White
• It is given as 8.732 liters in The Oxford Handbook of Engineering and Technology in the Classical World, edited by John Peter Oleson
• According to Pliny’s Natural History (18.66), 1 modius of wheat weighs between 20-21.75 librae (Roman Pounds) or 6.55-7.12 kg).

Carolingian Modius -- According to Verhulst and Grierson-Blackburn, it is suspected that in 793-4, Charlemagne increased the size of the official modius by 50%. This would make the new modius equal to about 13.1 liters.

Bonarius (aka Buonarius, pl. b(u)onarii) -- a measure of area used in the Carolingian Empire, given as 1.38 hectares (or 3.41 acres) in The Carolingian Economy (Cambridge Medieval Textbooks)
, by Adriaan Verhulst. “The normal occupancy of a mansus is one tenant [family] and it’s legal size is 16 bonarii.” p. 45. 16 bonarii is 54.56 acres.

Iornales (aka Iurnales) -- this word appears not to be a unit of measurement, but rather a vague word meaning “plowlands”.