For just as the Holy Spirit by nature and according to essence exists of God the Father, so too by nature and according to essence is the Spirit of the Son, insofar as the Spirit proceeds essentially from the Father ineffably through the begotten Son, giving its own proper energies, like lamps, to the lampstand—that is, to the Church.

- St. Maximus the Confessor, On Difficulties in Sacred Scripture: The Responses to Thalassios, 63.7.

The only thing from Eriugena that might seem Greek (on this matter of the Filioque) is that he says the reason why the Greeks didn't put "only proceeds from the Father" is because they wanted to leave open the idea that temporally (not substantially or hypostatically), that the Spirit at times was temporally sent in the bringing of the Son in the world (such as when the Spirit helped the Bl. Virgin Mary conceive) and also because the Spirit is involved in the giving birth to the Son in the souls of the Christians in the sacramental act of Baptism. In both these cases these are temporal, and the Greeks see these as being cases where the Spirit is the forerunner of the Son being sent.

"Those of the Queen of cities have attacked the synodal letter of the present very holy Pope (Martin I), not in the case of all the chapters that he has written in it, but only in the case of two of them. One relates to theology, because it says he says that ‘the Holy Spirit proceeds (ἐκπορεύεσθαι) also from the Son… With regard to the first matter, they [the Romans] have produced the unanimous documentary evidence of the Latin fathers, and also of Cyril of Alexandria, from the sacred commentary he composed on the gospel of St. John. On the basis of these texts, they have shown that they have not made the Son the cause of the Spirit — they know in fact that the Father is the only cause of the Son and the Spirit, the one by begetting and the other by procession; but in order to manifest the Spirit’s coming-forth (προϊέναι) through him and, in this way, to make clear the unity and identity of the essence…. The Romans have therefore been accused of things of which it is wrong to accuse them, whereas of the things of which the Byzantines have quite rightly been accused [monothelitism], they have, to date, made no self-defense, because neither have they gotten rid of the things introduced by them." - St. Maximus the Confessor (Letter to Marinus).

The Son was begotten by the Father alone, not made or created. The Holy Spirit was not made or created or begotten, but proceeds from the Father and the Son. ... Anyone, then, who wishes to be saved must feel thus about the Trinity." - St. Caesarius of Arles, The Beginning of the Creed of St. Athanasius, Sermon 3

“And if we bear in mind all the propositions made concerning God in the previous discussion, we shall admit that God the Son proceeded from God the Father, and the Holy Ghost from both, and that They cannot possibly be spatially different, since They are incorporeal.” - St. Severinus Boethius, De Trinitate

“By nature (phusei) the Holy Spirit according to the essence (kat’ousian) takes substantially (ousiodos) his origin (ekporeuomenon) from the Father through the Son who is begotten.” - St. Maximus the Confessor, Quaestiones ad Thalassium, LXIII

* Symeon endured severe opposition from church authorities, particularly from the chief theologian of the emperor's court, Archbishop Stephen, who at one time was the Metropolitan of Nicomedia. Stephen was a former politician and diplomat with a reputation for a thorough theoretical understanding of theology, but one which was removed from actual experience of the spiritual life. Symeon, in contrast, held the view that one must have actual experience of the Holy Spirit in order to speak about God, at the same time recognizing the authority of noscripture and of the earlier church fathers. Their differing views on the source of authority to speak on spiritual matters was the cause of several years of intense conflict, ending with Symeon's eventual exile.

Stephen found fault with Symeon especially for his charismatic approach, and his support of individual direct experience of God's grace. Symeon believed that direct experience gave monks the authority to preach and give absolution of sins, without the need for formal ordination—as practiced by his own teacher, Symeon the Studite. Church authorities also taught from a speculative and philosophical perspective, while Symeon taught from his own direct mystical experience.[15] Symeon's teachings, especially those regarding the direct experience of God's grace, brought accusations of heresy from Stephen. Symeon responded to Stephen's charges by declaring that the real heresy was to teach that it is impossible to have direct experience of God (Disc. 29.4).

These quotes are from the SVS translation of Symeon's hymns ( Divine Eros: HYMNS OF ST SYMEON THE NEW THEOLOGIAN, Daniel K. Griggs, SVS Press, Hymn 15):

"For while we become many members He remains one and indivisible,and each part is the whole Christ himself. And so thus you well know that both my finger and my penis are Christ." - Symeon the New Theologian, Hymn 15

"Thus it happened even now in the final age.Symeon the holy, the pious Studite,he was not ashamed about the members of any person,neither to see any naked people nor to be seen naked;he possessed the whole Christ, he was the whole Christ himself, and all his members and the members of every other he always saw one and all as Christ,and he remained unmoved, innocent, and dispassionate,since he was the whole Christ himself, and he saw all the baptized, who have put on the whole Christ as Christ." - Symeon the New Theologian, Hymn 15

"They glorify the compassionate one, they yearn for the beautiful one,and they are all united to the whole of his love, what is more, they acquire the holy seed, as we said,receiving the whole transformed God within themselves." - Symeon the New Theologian, Hymn 15

"They are hidden members of Christ, for they are covered,and on account of this they are more revered than the rest, as hidden members of Him Who is hidden, they are unseen by all, from Whom seed is given in divine communion, awesomely deified in the divine form,from the whole divinity itself, for He is God entire," - Symeon the New Theologian, Hymn 15

"According to St. Augustine the heretical sect of the Manichaeans consumed human seed as their own satanic "Eucharist". Symeon the New Theologian taught in 15th Hymn that the Eucharist was the "seed of Christ" which brings to mind the Manichean heresy. The Bishops of the East at the time were not found of Symeon for this and other teachings. The Bogomil sect (a offshoot of Manichaeanism) was founded in the East not long before the schism which may have been a influence on Symeon."

https://www.academia.edu/37240171/HUMAN_SEMEN_EUCHARIST_AMONG_THE_MANICHAEANS_The_Testimony_of_Augustine_Reconsidered_in_Context_CHAPTER_SIX_IN_FORTHCOMING_BOOK_AUGUSTINE_and_MANI_COLLECTED_ESSAYS_ON_MANI_MANICHAEISM_AND_AUGUSTINE_LEIDEN_BOSTON_BRILL_2019_

"Symeon's teachings on the hearing of confession and the absolution of sins brought him into regular conflict with church authorities, particularly Archbishop Stephen. According to Symeon, only one who had the grace and direct experience of God was empowered by God to preach and absolve the sins of others. Stephen held the view that only ordained priests had that authority. Symeon's views were colored by his own spiritual father, Symeon the Studite, who was a simple monk, unordained, and yet who preached and gave absolution. In one of his Ethical Discourses Symeon went further and wrote that one should not give absolution without having first received the experience of God's grace:

Be careful, I beg you, never to assume the debts of others when you are a debtor yourself; do not dare give absolution without having received in your heart the One who takes away the sin of the world." (Eth. 6')"

Two articles on Symeon The "New Theologian"s innovative trinitarianism" (even by Byzantine standards). EOs would re-interpret it by saying that proceeding from the essence, means proceeding by means of natural energy which would equate to the ever vague "Energetic Procession".

https://www.academia.edu/34952708/_The_Procession_of_the_Holy_Spirit_from_the_Divine_Substance_Observations_about_the_Trinitarian_Theology_of_Symeon_the_New_Theologian_and_Nicetas_Stethatos_Greek_Orthodox_Theological_Review_60_2015_75_91

- https://www.academia.edu/10614527/_Reconfiguring_the_Trinity_Symeon_the_New_Theologian_the_Holy_Spirit_and_the_Imago_Trinitatis_Byzantion_81_2011_212_236