Trading as we think of it today first began during the Bronze Age at around 4000 BCE. The first bronze tools were being developed. The Bronze Age had a major impact on the politics and economy of the world. This impact was seen in trade in that it became necessary. Many places couldn't find some of the materials such as copper and tin that they needed to make bronze tools, so they were forced to trade for it. The next main venue of trade that is seen in history is that of nomadic people. Nomadic people were essential to trade in the classical period. They were often the only means of contact from civilization to civilization. One of the most famous elements of trade brought to civilization by nomadic people was the silk routes. The silk routes ran from western China across the steppes of central Asia, all the way to Mesopotamia. They were the main venue of trade from around 1000 BCE all the way up until Rome. Although in some cases the nomadic people made trade over these routes more difficult, many pastoralist groups played critical roles in the trade of this area. Many merchants and governments paid the nomadic people to protect their caravans as they made their way across these routes. Some nomadic groups supplied animals for use in the caravan. Some nomadic groups even took the trading and did it by themselves, although this was uncommon. The silk routes were not only used for trading items however. Ideas were also spread through these routes. Religions such as Buddhism and Islam spread along the routes and were spread through Asia, Persia, and Africa. The routes also played vital roles in the spread of new inventions such as paper and gunpowder. Even some of the nomads" technologies such as the bit and saddle were used by the civilized peoples. Although the silk routes had such a positive impact on the world at this time, it also had its share of the negative. Disease and Plagues, notably the Black Death, were spread by way of trade routes.