Dolia were large earthenware jars designed mainly for the storage of foodstuffs. They differed from other types of ceramic pot by their great holding capacity, coarse temper and long-coil construction. Considered to be the largest terracotta containers ever made, dolia of the Roman period could hold between 500 and 3,200 litres. They were built at various production centres around the Mediterranean between the sixth century BC and the third century. 
In the Roman period dolia were mostly used in wine and oil cellars for vinification and storage. 
Omnipresent on terrestrial Roman sites, dolia were also used between the late first century BC and the middle of the first century as holding tanks in boats which specialized in transporting wine in bulk. Their size and shape varied according to when they were built and where they were going to be installed. The smallest dolia, and also the oldest, had a capacity of between fifty and ninety litres. It was during the Early Roman Empire that dolia attained their greatest size, with examples holding between 600 and 3,200 litres.