The Martini is one of the most famous cocktails in the world, but its exact origin is uncertain.
The strongest historical theory is that it evolved from the Martinez, an older 19th-century cocktail made with gin, sweet vermouth, liqueur, and bitters. Historians generally treat the Martini as part of that family tree rather than a drink invented in one clean moment by one person.
One key milestone is that an early printed Martini recipe appeared in Harry Johnson’s 1888 bartending manual. That version was sweeter than the modern Martini, calling for Old Tom Gin, sweet vermouth, orange curaçao, orange bitters, and gum syrup. In other words, the original Martini was not the ultra-dry drink many people picture today.
Over time, the drink shifted from sweet to dry as gin styles changed and dry vermouth became more central. That gradual evolution is what produced the classic modern Martini: usually gin and dry vermouth, stirred and served up, often with an olive or lemon twist.