It was much more complicated in the middle ages. No kilograms and hundrets kinds of units in Czech lands instead. Just for your interest I copied this from one website, to see how many units were used and what chaos existed I highlighted the pounds.
České staré váhové míry (Old czech weight measures)
lékarnický grán 0,073 g
karát metrický 0,2 g
karát vídeňský 0,206 g
denár 1,0034 g
lékárnický skrupul 1,458 g
kvintlík 4,0137 g
lékarnická drachma 4,375 g
lot 16,05 g
lot celní 16,66 g
lot vídeňský 17,5 g
lékarnická unce 35 g
česká hřivna 256,875 g
vídeňská hřivna stříbra 280,668 g
libra lékarnická 420 g
libra česká 513,75 g (czech pound)
libra pražská 514 g (prague pound)
libra slezská 530 g (silesian)
libra celní (= 32 loty) 541 g
libra celní (nová) 500 g
libra vídeňská 560 g (vienna)
kámen 10,275 kg (10,288 kg)
cent (= 100 liber) 51 kg
cent vídeňský 56 kg
As you can see, it’s insane . There is (besides the rest) many kinds of pounds, becouse a lot of regions or cities used their own measuring. So you can see there also Silesian or Vienna pound with slightly different numbers. But as a base unit in game it’s most logical to use czech (or prague) pound obviously.