Let F be a field and p an
F-polynomial. We say that p is F-real if and only if every real closure of F contains
the splitting field of p over F. Our main purpose is to prove
Theorem 1. Let F be an algebraic number field and p a monic F-polynomial with
an odd degree factor over F. Then p is F-real if and only if it is the characteristic
polynomial of a symmetric F-matrix.