[Medieval manuscript from the 13th century showing barrow usage including the transportation of children.]
The mighty wheelbarrow. An invention that we take for granted, but was an innovative feature of Medieval life. The wheelbarrow along with about 1.000 other creations that could be named, puts a lie to the 'Dark Age' myth. I would suggest people watching reality tv, believing that trace chemicals cause weather; praying to the god of the state; or reading 'scientists' like Hawking who believe that aliens seeded life on earth with space-dust, represents a Dark Age. The great and good of the modern world have enough trouble using a wheelbarrow, let alone inventing one.
The modern wheelbarrow was invented during the Carolingian period when building large public projects began anew. When Rome declined into 3 Germanic Kingdoms, issues with collecting tax money, social stability, civil peace and central governance made large-scale project development a very difficult proposition. With the quasi-Pax of Charlemagne in the early 9th century; building projects for private and public usage, were deployed. It was during this era that an unknown inventor, or perhaps a group of working men tired of using only human power, created a usable, deep, high-sided moving container. From France the wheelbarrow spread to the Low Countries, Germany and the British Isles.
To the modern urban-condo-4 foot wide townhome-dweller, the wheelbarrow looks rustic, 'simple', obvious, something that only a 'redneck would use'. These urban geniuses should try inventing something rustic, simple and obvious. The barrow transformed agriculture, building sites, and materials-usage. Productivity, the key to improving our standard of living, was directly and measurably impacted by the barrow. Stones could be moved. Food production more quickly brought to milling and market. Debris removed. Nutrients, dung and fertilizers brought with ease to the fields being tilled. Seeds rolled into place for distribution. Transportation issues of supply, product and tools, over short distances were resolved. Productivity, as given by the enormous increase in population and living standards starting around 900 A.D., proceeded apace, in part fuelled by this 'simple' device. The barrow is one reason why Europeans by 1000 A.D. were wealthier, bigger and better fed than any other society in the world.