Word to the wise: the Dena (Danish) Pirates and Frankish Raiders are lethal. A travel advisory is in effect for the areas of Kent, the Fens, and East Anglia. Don't go there until you have at least 100 good men. Heavy infantry are everything, archers suck but have a few uses, and cavalry is for pursuit of routing enemies rather than combat.
I often build a lair in the Fens close to the Dena landing. One of Brytenwalda's options is "Realistic Casualties"; basically, the losing side has a good chance to have some of its troops knocked out and available to take as prisoners, even if you killed them in battle. So when I defeat the Dena, I take prisoners, and with the help of CHA/Leadership/Persuasion, I convince them to join my party. However, on the first night of serving with your army, there's a high chance that at least some recruited prisoners will escape, unless you put them in the garrison of a castle, town, or your lair (which you can build from the camp menu with a certain amount of renown and 20,000 scillingas). After the night has passed, I put them back in my army. Recruiting the people who just tried to kill you naturally makes your army take a huge morale hit, so I treat them all to beer and whores at the nearest tavern.
Also important: certain units can act as specialists. Shepherds increase your party's foraging skill, priests can increase morale in battle, I think, and can be paid to raise morale outside of battle, camp women can as well, standard bearers can raise morale in battle, spies can be sent to investigate towns and castles (but usually get caught), and so on.
Siegecraft has been totally reworked. build sanitation to avoid disease, and build mantlets to reduce casualties when deploying the engines. The good news is there's an exploit that lets you build those instantly (just start building them, then click the map while you're waiting to interrupt and they'll be built). Fortifying your camp is a good idea, and really helps in the field when outnumbered, too.
