this wing too was all cavalry , but where the right was a mailed fist of knights and heavy lancers , the vanguard was made up of the sweepings of the west : mounted archers in leather jerkins , a swarming mass of undisciplined freeriders and sellswords , fieldhands on plow horses armed with scythes and their fathers ' rusted swords , half-trained boys from the stews of lannisport ... and tyrion and his mountain clansmen .