Depiction of Saxons
The Saxons are portrayed as farmers who clear the land for cultivation of grain. They are also experienced in using wood to build ships. Their villages are in the middle of their fields and they are not fortified, since they can recognise approaching enemies earlier than the Celts who live in glades. ("The Gift of Life" and the flashbacks in "The Prisoner" provide an impression of Saxon villages.) The Saxons are brave footsoldiers but they are defeated by even a smaller number of Celts if they fight as cavalrymen. (As demonstrated in "The Duel".) So instead of invading Britain they just infiltrate it as clans (and that is how Arthur describes it in "The Challenge"), fighting with Celtic clans for places that suffice to make a living as farmers.
Read more about this topic: Arthur Of The Britons