  Local conserved charges in principal chiral models in 1+1 dimensions are
investigated. There is a classically conserved local charge for each totally
symmetric invariant tensor of the underlying group. These local charges are
shown to be in involution with the non-local Yangian charges. The Poisson
bracket algebra of the local charges is then studied. For each classical
algebra, an infinite set of local charges with spins equal to the exponents
modulo the Coxeter number is constructed, and it is shown that these commute
with one another. Brief comments are made on the evidence for, and implications
of, survival of these charges in the quantum theory.
