From Wikipedia

Ancient Worlds - Come Together

The level of advancement of a civilisation is often measured by its progress in agriculture, long-distance trade, occupational specialization, and urbanism. Aside from these core elements, civilisation is often marked by any combination of a number of secondary elements, including a developed transportation system, writing, standards of measurement (currency, etc.), contract and tort-based legal systems, characteristic art styles (which may pertain to specific cultures), monumental architecture, mathematics, science, sophisticated metallurgy, politics, and astronomy.