Like Vodka, Gin was developed as a medicinal spirit, historically lower in proof than it is today. While most spirits are defined by their base ferment, Gin is a neutral grain spirit flavoured with herbs, most notably juniper berries.
Originating in the Netherlands, it spread to England around the time of the Dutch William of Orange sat on the English throne. As a result in the 17th century, it became enormously popular in England.
The style of London Dry Gin was in contrast to the Jenever gin flavoured with Juniper, which was often sweetened. London Gin was produced on a column still, and had a lighter, clean flavour that was not sweet.
The British love of the tipple spread to India, where colonials would mix gin with water and quinine, which was used to prevent malaria, giving rise to the still popular Gin and Tonic.
Today, Jenever is a protected appellation in the EU, and it is still produced on pot stills to create more character and personality. Other variations include Old Tom Gin, an out of style Gin that was oak aged and somewhat sweet. Still in use today, Sloe Gin is a liqueur made from macerating gin with sloe berries and sugar.