In this note we consider a special of the problem of diagonalizing hermitian matrices of continuous functions. We say that a hermitian element Aϵ Mn(C[a,b]) is diagonalizable if there is a unitary element Uϵ Mn(C[a,b]) such that U*AU is diagonal. Thus,for each t ϵ [a,b], U(t)*A(t)U(t) is diagonal, and in particular each U(t)is unitary. We do not know who first realized that hermitian elements of Mn(C[a,b]) cannot, in general, be diagonalized,but evidently this is folklore.