Records of cash, commodities, and transactions were kept scrupulously by military personnel of the Roman army. An account of small cash sums received over a few days at the fort of Vindolanda circa 110 CE shows that the fort could compute revenues in cash on a daily basis, perhaps from sales of surplus supplies or goods manufactured in the camp, items dispensed to slaves such as "cervesa" (beer) and "clavi caligares" (nails for boots), as well as commodities bought by individual soldiers. The basic needs of the fort were met by a mixture of direct production, purchase and requisition; in one letter, a request for money to buy 5,000 "modii" (measures) of "braces" (a cereal used in brewing) shows that the fort bought provisions for a considerable number of people.