Salt

The one mineral, rather than plant or animal product, among this atlas's founding ingredients: sodium chloride, gathered by evaporating seawater or brine or by mining rock deposits, used across every cuisine on earth both to season and, before refrigeration, to preserve meat, fish and vegetables through curing and fermentation. Its production and control shaped taxation and trade routes across many historical states, but no single earliest-use date is honestly citable from the references this atlas draws on: salt gathering has no domestication event to date, unlike a cultivated crop, and the archaeological record of early salt working is scattered across many independent sites rather than one origin. Two documented trade networks show that control concretely. Rome's Via Salaria, the Salt Road, carried salt inland from pans near the mouth of the Tiber across the Apennines, a route already in use before Rome existed as a city; the English word salary does descend from the Latin salarium, but the popular story that Roman soldiers were literally paid in salt is a documented myth with no ancient source behind it, traced by classicists to a speculative entry in an eighteenth century Latin dictionary rather than to any Roman testimony. In West Africa, salt from Saharan mines such as Taghaza and Idjil moved south by camel caravan along trans-Saharan routes controlled chiefly by Berber traders, exchanged in some accounts pound for pound for gold at trading cities including Timbuktu and Djenne, underwriting the wealth of the Ghana, Mali and Songhai empires in turn across roughly a thousand years.