This is not true. For example, the Russian Orthodox Church had been a metropolitanate of the Patriarchate of Constantinople for a few centuries since its establishment in 988. Eventually she received independence (autocephaly) in 1589, and it is very important to note that this independence was received in a strict accordance with the Orthodox Canon Law, which is essential for all Canonical Churches. It clearly states the difference between an autocephaly and schism. Please see Autocephaly of the Russian Church for reference.
