When does timer begin for capturing central square?

[Hurin_Rules]

I've just completed my first campaign as the Julii. I have taken 47 provinces and now just need to take Rome, so I put together a 20 unit army with some reserves and march on the eternal city. The enemy sallies out and I defeat him; this is going to be easy, I'm thinking at this point. I have two armoured siege towers and ladders. For some reason, my troops ladders don't appear on the siege battlefield, but I think, no problem, I've still got the towers. I shove the towers up to the walls-- one of them doesn't deploy correctly but the other does, and my troops march over. They dispatch the two units on the walls with no real problem, and I take the gatehouse. Suddenly, the 3 minute timer appears. WTF? All I did was march my towers directly to the gatehouse, disperse the enemy and open the gate. I can't figure out why the timer started. I only have three minutes to move my troops throught the paths and AI pathing traps of a huge city. Needless to say, there's no way my infantry could have made it, and I actually had to put my cavalry on run simply to make it into the square. The enemy still had a couple of units there so I couldn't take Rome.

Now, the question I am asking is, Is this normal? I mean, why did the timer start when I took the wall? I've never had the timer start that quickly before. I marched my siege engines directly to the wall, encountered little resistance and yet still could not even in theory have had time to get my infantry into the central square. What gives?

[lancelot]

AFAIK the timer starts when either player has 3 minutes left or the last enemy in the square has been killed/routed. Whichever comes first.

[Akka]

I have two armoured siege towers and ladders. For some reason, my troops ladders don't appear on the siege battlefield
Ladders are only usable on Stone Walls, not on Large Stone Walls nor Epic Walls (they are too tall).

As for the counter, it's, AFAIK, as the previous poster said. Though it's strange, as you probably didn't took all but 3 mn to simply clear the walls.

[The_Emperor]

if the timer begins when you are outside then that is how long you have to kill EVERYONE inside. Capturing the Plaza doesn't help you because its timer starts from scratch and if the other one is already counting down it will expire before the Plaza one does.

Your only hope is to rush and hunt down every last enemy when the 'enemy win' timer starts ticking.

[Hurin_Rules]

Thanks!

All I guess I can say is that wow, that timer is short! How in the world do you take a heavily defended city in such a short time?

[Quillan]

Luck, skill, planning, and luck. Did I mention luck? For some reason, the allotted time you have to capture a city can vary widely, with no rhyme or reason I have been able to determine. Most of my open field battles have a 34-36 minute time limit, regardless of the number of troops involved, but I've had a 36 minute city assault time limit with 4 units assaulting a city with a wooden wall and a single unit defending, and a 19 minute time limit against a city with epic walls, a full 20 unit army defending and a 20 unit army attacking. I've learned to check the time limit during the deployment phase, and make my plans accordingly. The lowest time limit I have ever seen was 11 minutes, and it was a good thing that was a wooden wall, minimal defenders, and an open gate due to spies in the settlement.