The tree was probably indigenous to India or China, but it’s not yet been proven when the fruit made its way westwards into the Mediterranean. Citrus fruits may be visible in Roman mosaics, but these could be citron.

The earliest definitive cultivation of the lemon tree was in medieval Arabia, and the first description of a sweetened lemon drink can be found in Egypt during the time of the Crusades.

Starting in Tudor England, lemon juice was used in medicinal cordials called ‘Water Imperial’, along with cream of tartare, and would retain a healing reputation for centuries.

Samuel Pepys was one of many Londoners who, by the 1660s, was enjoying the refreshing new beverage of sweet lemon juice, mixed with honey and water, imported from France.

The addition of bubbles had to wait, however, until 1767, when English chemist Joseph Priestley invented carbonated water, a technique exploited by Johann Jacob Schweppe, whose commercial drinks company began selling fizzy soda in England in the 1790s.

By 1833, ginger beer and carbonated lemonade were widely available at Britain’s refreshment stalls.

Source:

http://www.historyextra.com/article/food/who-invented-lemonade

https://islamstory.com/en/artical/19477/Who-invented-lemonade