Yup - at least in Europe this backtracks all the way into the Middle Ages. And it was actually a big deal because the units were similar, neither completely identical nor completely different. And that was actually a big deal because people could argue which of those units they meant, specially when buying/selling stuff. (For example, let’s say that some Portuguese merchant agrees to sell “five tons of fish” to a random Englishman. Now you get:
the merchant arguing “five Portuguese tons”, expecting to sell 793*5=3965kg of fish
the buyer arguing “five English tons”, expecting to buy 1088*5=5440kg of fish
even if both were in good faith they’d feel themselves cheated on the deal.
To make it worse sometimes the units changed inside the same realm, over time.
Yup - at least in Europe this backtracks all the way into the Middle Ages. And it was actually a big deal because the units were similar, neither completely identical nor completely different. And that was actually a big deal because people could argue which of those units they meant, specially when buying/selling stuff. (For example, let’s say that some Portuguese merchant agrees to sell “five tons of fish” to a random Englishman. Now you get:
even if both were in good faith they’d feel themselves cheated on the deal.
To make it worse sometimes the units changed inside the same realm, over time.