The folks at Warhammer Online have posted a guide to city conquest, where they explain the process of City Sieges in the game.

The culmination of the ever-present conflict in Warhammer Online is the capture and ransacking of the enemy’s capital city. Herein we’ll detail the steps necessary for opening the gates of the city, and ultimately taking it for your realm. Later on, we’ll have more specific guides for each step along the way, but every razing and pillaging group of warriors must start somewhere, so let’s begin with the basics.

Opening up the gates of either city is a long and arduous process that begins in the Tier 4 zones primarily. In order to force your enemy’s city into the contested state, you and the fellow warriors of your realm must first capture 2 fortresses in the Tier 4 zones within 12 hours of each other.

In order to attack these fortresses, you must first capture the zones prior to the Fortress zones in Tier 4 by Zone Control (participating in Scenarios, queuing for Scenarios, capturing Objectives and Keeps, Killing enemy players and completing PQs). What this means is you’ll first push to a zone between your Tier 4 home and the enemy’s (Praag for example), and once you’ve taken control of that zone you would push forward to Reikland or Chaos Wastes (depending on your allegiance) and capture the objectives there.

Read more here.