Our main result, theorem 2.6, is to obtain a diagonalization theorem for hermitian elements A of M2(C[a,b]) in which we relax the condition that the eigenvalues of A(t) must be distinct for all t ϵ [a,b]. To do this we suppose A is continuously differentiable, and at those points t where the the eigenvalues of A(t) coincide, the eigenvalues of A'(t) are distinct