Gin as we know it stems from “Jenever”, a Dutch gin created with juniper berries and traditionally aged in casks. Gin was initially created for medicinal purposes, though became popular as a recreational drink during 17th century Britain. In this era, the government permitted unlicensed gin distilling, and as a result, surpassed beer in popularity, becoming prevalently served and consumed in London bars.
For British colonies overseas, gin would conceal the taste of quinine, the medication used to treat malaria. We can thank the colonies for G&T as we know it – quinine forming the primary flavour of tonic water.