Maximus the Confessor
Orthodox theologian and Metropolitan of Pergamon, [[John Zizioulas]], says: "For [[Maximus the Confessor|Saint Maximus]] the Filioque was not heretical because its intention was to denote not the ἐκπορεύεσθαι (ekporeuesthai) but the προϊέναι (proienai) of the Spirit."