Cattle stealing was a famous tradition in ancient Ireland. Heroes were praised in song for their ability to steal their neighbors' cattle. Many historical chronicles contain detailed descriptions of these deeds, and the Cooley Cattle Thief is even mentioned in the oldest and most important books of Irish mythology.

Kings commanded bands of cattle thieves during a ceremonial event called the "creach righ" to mark the beginning of a new monarch's reign. During this event, they would seize cattle from neighboring kingdoms as well as those of Viking raiders invading Ireland.
In the finale, rival neighbors stole each other's cattle from their pastures. In this game, you organize raids on your neighbor's pastures with the goal of stealing their herds.

In Tain, the player assumes the role of the leader of a small clan, seeking to seize the wealth and power of their neighbors. Throughout the game, you will send members of your clan to free livestock from the hands of your rivals, sneak into their homes, and search for hidden jewels. The one who gains the most wealth is the winner.