Legions is a simple and unique strategy game. Simply put your objective is to pick a nation and conquer the world with it. You can select from a number of historical or random situations, from 1200 BC to 800 AD. Each turn, you can manage your economy (deciding what to buy or sell, although your advisor takes care of the critical needs of food and supplies), build military units, handle diplomacy, and move your units. Each nation also has an 'elite' unit that includes the ruler. This unit is very powerful in battle, but if it is destroyed, your ruler is killed. Here's where one of the unique ideas comes into play, though -- you automatically get an heir to continue the game as long as you still have a major city.
To destroy another civilization, you need to take all their major cities AND kill their ruler(s). Plus, your nation needs to have a strong economic infastructure to support your military, since your towns/cities supply your economy, and supplies are needed to keep your units in the field. Without a strong economy, you will be forced to disband units and can not buy materials to build more. This is a feature today's crop of games should have. It's also quite easy to learn how to play.