  In 1896 Frobenius and Fricke had published two seemingly unrelated papers:
Frobenius had started to develop his theory of $k$-characters for finite groups
motivated by Dedekind's question about factorisation of the group determinant,
while Fricke followed Klein's approach to the uniformization theorem. We show
that in fact these two works can be naturally linked and both are related to
remarkable Markov's paper of 1880 on arithmetic of binary quadratic forms.
