The way a fork works is instead of creating a totally new cryptocurrency (and blockchain) starting at block 0, a fork just creates a duplicate version that shares the same history. So all past transactions on bitcoin cash’s new blockchain are identical to bitcoin core’s blockchain, with future transactions and balances being totally independent from each other. For practical matters, all this really means is that everyone who owned bitcoin before the fork now has an identical amount of bitcoin cash that is recorded in bitcoin cash’s forked blockchain.

https://techcrunch.com/2017/08/02/wtf-is-bitcoin-cash-and-is-it-worth-anything/?ncid=rss&utm_source=dlvr.it&utm_medium=twitter