Commerce and manufacturing certainly occupied a significant place in the early Roman economy. Large landowners and small farmers depended for their livelihoods on the production of surpluses for the market. In Roman agriculture, most common method for cultivating wheat was the two-field system. The Roman empire also witnessed construction of modest sized-estates which regularly included a pars urbana, an often lavishly adorned farmhouse, and a pars rustica, included farming facilities such as those for pressing grapes. Sometimes, many landowners used the institution of farm tenancy to organize the management and labor on their estates. To answer the question of what extent wealth generated from agriculture contributed to an expansion of production in the non-agricultural sectors of the Roman economy, the economic role of cities in the Roman empire and their relationship with the countryside, has to be evaluated. Archaeological evidence indicates that mining was conducted on a widespread basis in many regions of the Roman empire.