Constantine  saw  his  opportunity,  and  by  a  rapid
turning  movement  gained  the  Via  Cassia^^and  fell  on
Maxentius'  rearguard  at  the  passage  of  the  Tiber,
where,  beside  the  permanent  road-bridge,  pontoons
had  been  thrown  across  the  river.  The  legions  of
the  Rhine  fulfilled  the  task  for  which  they  had  been
trained  by  their  leader,  .and  their  victory  'was  com-
plete and  decisive.  The  Tiber  was  swollen  by
autumn  rains — it  was  the  27th  of  October — and
many  thousands  of  the  enemy,  amongst  them  Max-
entius himself,  were  swallowed  up  in  its  yellow
waves.
