The history of Roman Law can be divided into three systems of
procedure: that of legis actiones, the formulary system, and
cognitio extraordinarem. The periods in which these systems were
in use overlapped one another and did not have definitive
breaks, but it can be stated that the legis actio system
prevailed from the time of the XII Tables (c. 450 BC) until
about the end of the 2nd century BC, that the formulary
procedure was primarily used from the last century of the
Republic until the end of the classical period (c. AD 200), and
that of cognitio extraordinarem was in use in post-classical
times. Again, these dates are meant as a tool to help understand
the types of procedure in use, not as a rigid boundary where one
system stopped and another began. Legis Actiones  The remarkable
aspect of a trial of an action under the legis actio procedure
(and also later under the formulary system) was characterized by
the division of the proceedings into two stages, the first of
which took place before a magistrate,