The province in Online will be very similar to that in Oblivion, just much larger. It will be bigger than Skyrim in Elder Scrolls V. The whole province will be opened to players, and there will be many small towns to fight over.  Players will be able to battle over farms, windmills, and lumber mills for resources, as well as fight for major cities such as Kvatch, Anvil, Bravil, Bruma, and the Imperial City.
The province will be the main area for PvP in TESO, but will also contain imperials (which won't be a playable race), the undead, and daedric creatures. Whichever faction captures the Ruby Throne in the Imperial City will be able to crown one of its members as emperor of Tamriel. Being crowned emperor gives the "new emperor" special attributes and advantages. There will be Elder Scrolls, that a faction can take, which will give everyone in the faction bonuses. The catch is that you must capture the Elder Scroll, protect it, and take it back to your faction's stronghold in Cyrodiil. A faction can conquer another one's stronghold and take the scrolls, but they will do no good unless they can protect them and take them back to their faction's stronghold. A player can enter Cyrodill at level 10, and he/she will automatically be maxed out to level 50 (only in Cyrodill), but you may want to keep playing the PvE part, so you can get better weapons and armor to better yourself.