mountains of Afghanistan was the largest source for trade of lapis lazuli. The material was most largely traded during the Kassite period of Babylonia beginning 1595 BCE. Later trade Mediterranean and Near East Ebla was a prominent trading center during the third millennia BCE, with a network reaching into Anatolia and north Mesopotamia. Materials used for creating jewelry were traded with Egypt since 3000 BCE. Long-range trade routes first appeared in the 3rd millennium BCE, when Sumerians in Mesopotamia traded with the Harappan civilization of the Indus Valley. The Phoenicians were noted sea traders, traveling across the Mediterranean Sea, and as far north as Britain for sources of tin to manufacture bronze. For this purpose they established trade colonies the Greeks called emporia. Along the coast of the Mediterranean, researchers have found a positive relationship between how well-connected a coastal location was and the local prevalence of archaeological sites from the Iron Age. This suggests that a location's trade potential was an important determinant of human settlements. From the beginning of Greek civilization until the fall of the Roman Empire in the 5th century, a financially lucrative trade brought valuable spice to Europe from the far east, including India and China. Roman commerce allowed its empire to flourish and endure. The latter Roman Republic and the Pax Romana of the Roman empire produced a stable and secure transportation network that enabled the shipment of trade goods without fear of significant piracy, as Rome had become the sole effective sea power in the Mediterranean with the conquest of Egypt and the near east. In ancient Greece Hermes was the god of trade (commerce) and weights and measures. In ancient Rome, Mercurius was the god of merchants, whose festival was celebrated by traders on the 25th day of the fifth month. The concept of free trade was an antithesis to the will and economic direction of the sovereigns of the ancient Greek states. Free trade between states was stifled by the need for strict internal controls (via taxation) to maintain security within the treasury of the sovereign, which nevertheless enabled the maintenance of a modicum of civility within the structures of functional community life. The fall of the Roman empire and the succeeding Dark Ages brought instability to Western Europe and a near-collapse of the trade network in the western world. Trade, however, continued to flourish among the kingdoms of Africa, the