Quickest collapse you've seen?

[_Aetius_]

One of the biggest collapses ive personally ever had was as Egypt in Vanilla. It was fast considering I was playing and you would expect players empire not to collapse as mine did, but anyway.

Background

I'd gotten into a position where I was at war with all my major potential trading partners so wasnt making any money, but I still needed a massive army to hold my empire together. Discontent was rife but I was holding things together, my empire was from Tunisia to Bulgaria, Armenia to Arabia, basically everything between those points.

The problems arose when I was forced to invade Italy because of persistant Sicilian attacks on my naval forces, I didnt have many native troops to spare so had to hire mercenaries locally. When Sicily, Naples and Malta where under my control the Papacy declared war and I was forced to keep a considerable mercenary army stationed in Naples. During this brief 5 year campaign a new Sultan had come to the throne with very poor influence, so to lose my recent conquests by disbanding disloyal units would of been catastrophic.

The cost of maintain my empire which needed huge garrisons in Africa to fight the war with the Almohads, massive garrisons in the Balkans to hold back the Hungarians and rebelling Byzantines and a large force in Armenia and Trebizond to hold the Mongols was breaking my economy. I also needed large garrisons in the provinces to.

Start of collapse

The breaking up of the empire began when the current Sultans brother rebelled in Anatolia, it wasnt huge but it was enough to stretch me to far. I had to neglect my western armies to deal with repeated rebellions and invasions in the east during this time. My most loyal generals were pulled east and clustered together with my relief armies leaving less loyal men in charge of the west, something I simply couldnt avoid.

In the middle of this madness the mercenary army in Italy rebelled and a major civil war broke out led by yet another brother in Syria, of a total number of 3,500 men in and around Italy 2,800 joined the rebels. So I instantly lost control of my most recent conquests, thousands more men rebelled throughout the empire including a large army of reinforcements i'd sent to smash the forces of the last rebel army in the previous civil war.

About 50% of the empire was either rebel or being fought over, I lost most of the interior of Asia Minor and every island I had, worst of all my army in Tunisia was fighting itself as half was rebel the other still mine and the Almohads launched a massive offensive and crushed both sides at once and marched on Egypt.

Outcome

Over the next 10 years my empire was dismantled, I ended up with about 20% of what I had had 20 years earlier. I managed to withdraw enough men in time from the Balkans to secure the holyland and repel the Almohads, but couldnt withdraw over 800 men stranded on Sardinia thanks to enemy fleets nearby. Sardinia was eventually lost a few years later along with several important generals.

The main collapse probably took place over about 8 years the following 10 just summed up the chaos that followed, repeated rebellions and ridiculously large invasions. What I performed was a series of large withdrawels to the interior of the empire. I feel that I couldnt of done any better than I did, I was caught in a situation where I needed a massive army my economy couldnt afford to defend the heartlands where my economy was based.

I did recover, but for what ever reason provinces were constantly disloyal to me and I could never expand, but I did get my revenge in Italy and utterly smashed the mercenary army. However I did have to withdraw again, because of you guessed it a rebellion

I've never been huge and literallylost everything before, thats the closest ive ever come to being a superpower to nothing.