Civilian unit for expanding your empire.
The Settler is used to found a new city. All civilizations and city-states begin the game with at least one Settler, but city-states (and Venice) cannot produce more. To build new Settlers, a city must have at least 2 Citizens. On lower difficulties Settlers can also be found in Ancient Ruins.
While a city is producing Settlers, population growth is paused. This prevents a city from growing during Settler production but also prevents it from starving. Any surplus Food in the city is converted into Production at a diminishing rate, with a point of Production granted at the first, second, fourth, and eighth surplus Food and every fourth Food onward. This conversion process helps reduce the negative impact of Settler production in cities with more excess Food, so that it is not always optimal to produce a Settler in a city with the most Production and least excess Food.
Like other non-military units, Settlers cannot defend themselves and are easily captured unless protected by a combat unit. A Settler captured by a different civilization immediately becomes a Worker.
Pioneers drive civilization. While most are satisfied with the status quo, happy just to survive, in every culture there are a few hardy individuals willing to strike out on their own, to risk everything in the hope of finding a better life for themselves and their children. In the past, brave settlers have led humanity out of Africa and into Europe, Asia, the Pacific, and the Americas. In the future they may lead the way to the moon, Mars, and even beyond.