Bitcoin Gold (BTG) is a Bitcoin hard fork that took place in 2017. The initial goal behind creation of Bitcoin Gold was to increase level of decentralization of Bitcoin network as it became obvious that most of the network is controlled by few mining pools.
Bitcoin is the first cryptocurrency created in 2009 by a person or group of people under the name of Satoshi Nakamoto. Bitcoin was proposed as an alternative to the conventional banking system in the wake of the financial crisis of 2008. Unlike banks, the Bitcoin network is a decentralized anonymous peer-to-peer payment system designed to the way that it is almost impossible for a single entity to gain control over this network.