to enter the lists

from The Collaborative International Dictionary of English v.0.48

List \List\ (l[i^]st), n. [F. lice, LL. liciae, pl., from L.
   licium thread, girdle.]
   A line inclosing or forming the extremity of a piece of
   ground, or field of combat; hence, in the plural (lists), the
   ground or field inclosed for a race or combat. --Chaucer.
   [1913 Webster]

         In measured lists to toss the weighty lance. --Pope.
   [1913 Webster]

   {To enter the lists}, to accept a challenge, or engage in
      contest.
      [1913 Webster]