Original: As the system developed in the seventh century, the vassals were gangs of freemen who voluntarily subjected themselves, in some varying degree of formality, to the authority of a leader, from whose distribution of loot they could expect to be fed, clothed and armed.
Simplified: As the system developed in the seventh century, the vassals were gangs of freemen who subjected themselves, in some degree of formality, to the authority of a leader, from whom they could expect to be fed, clothed and armed.