I've been playing as an average Doux in ERE, with my son being the heir to it (some daring intrigues and wise marriages by my mother). So, when my son got the Imperial throne, of course both Seljuks and Fatimids attacked. I've had some money saved, so after hiring a bunch of mercenares I've managed to incur some casualties to both invading countries and even break couple of doomstacks. Then my "genius" son managed to waste all Imperial troops, resetting warscores. Afterwards he would send his not-yet-replenished troops to death, while I'll somehow manage to break yet another doomstack that incured defeat on him. Meanwhile, Pope was generously providing me with money for more mercs, attempting to retake Rome from me and conceding defeat in a year. The warscore was around -20% to 20% for hefty 28 years. In the end, my Doux died and I've became the Emperor, bringing a swift ending to both wars.
) took the throne. Duke of Armenia (also from my dynasty) declared war to put different claimant and get huge free stack (he was even stronger than me). So I was attacking holdings after he left province and the war continue. Also Cumans declared was for one province, which Armenia hold in de jure Cumans and capture it, but couldn't make peace with Armenia, score didn't even start rising. Due to this Armenia couldn't make a peace with Empire and war continue. It last over 30 years, in this time there were also 2 muslim invasions. This war was good for me so I was supporting Emperor only a little, so I was sure he won't loose title. After over 30 years and Armenian running through Empire, they lost most of their stack. Also they started besieging me so that was enough - I've crushed Armenia and they finally made peace with Cumans and after it Byzantium. I guess war could last longer, but besieging my personal holdings was too much for me...