Netstorm is an old RTS that came out for Windows 95 and still has a strong following with patches and updates by fans at NetstormHQ.com
You and your opponent (or opponents in multiplayer) are on separate islands and must build bridges to connect and reach out to islands that have resources. If you build your bridges fast enough you can go around back or block off your enemy from getting close to you.
The gameplay is typical were you must build more and get more resources to get upgraded weapons. The weapons however cannot be controlled, usually have just a single line of fire and will shoot only the first thing they see until its destroyed, even if something comes closer. But that makes for different kinds of strategies. There are also flying weapons.
You must get the other priest in your line of fire and stun him, tell a worker to capture him, and then sacrifice him.
You can download it at
http://www.netstormhq.com
http://www.youtube.com/v/9Cz_SkFrovA&rel=1