I have a playthrough called Usuno the Roman (well by now most call him Dux Britanniarum), where I basically set out as a noble son of Romano-British descent. I spent a LOT of time trading and doing tournaments at first, relying on my skill in the arena to pay and equip my companions as the new Sarmatian knights of Arthur (armored greek horses and wolf loricas for seven combat companions). I also got a LOT of recruits killed, hunting down dena pirates and franks whenever possible and taking them down en masse with the My Wife 2handed axe. I would always keep danes, ship captains, and franks, and recruit them into my army (and drop them in my lair to keep them from escaping immediately). Any other faction troops I recruited I used in my foreigner-collecting army, and eventually I had two armies of about 150 each.
One was my field army of auxilia which always accompanied me and was made of mostly rescued prisoners from all factions, along with the occasional injection of peasant leves. Angles, saxons, britons, even some eiru and picts in this army, of whatever quality I could find. They were expendable and I used them to kill bandits and get slaughtered by dena pirates.
The second army stayed in my lair Castrum Usunorum, an army of elite dena and frankish legionaries, complete with ship captain centurions. This army of legionaries I unleashed on an unsuspecting Lundenwic after talking to Virio, and my auxilia soaked up most of the siege casualties. Once my denas and franks got inside the walls, nothing could stop them, and a new Roma began at Londinium. This actually took a lot longer than I thought, but the benefit of that was that I'd found and sent out almost every companion by then, so no one declared war on me after I wiped out east seaxe.
