Filioque

===Possible earliest use in the Creed===
Some scholars claim that the earliest example of the {{lang|la|Filioque}} clause in the East is contained in the West Syriac recension of the profession of faith of the [[Church of the East]] formulated at the [[Council of Seleucia-Ctesiphon]] in Persia in 410.{{sfn|Price|Gaddis|2005|p=193|ps=:"We acknowledge the living and holy Spirit, the living Paraclete, who [is]<!-- bracketed interpolation as in Price & Gaddis --> from the Father and the Son."}}{{efn|Indications of "filioque language can also be found in certain early Syriac sources," according to {{harvtxt|Plested|2011}}.}} This council was held some twenty years before the [[Nestorian Schism]] that caused the later split between the [[Church of the East]] and the Church in the Roman Empire.<ref>{{cite book |last=O'Leary |first=De Lacy |author-link=De Lacy O'Leary |title=The Syriac Church and Fathers |publisher=Society for Promoting Christian Knowledge, London 1909, reproduced by Gorgias Press |year=2002 |isbn=978-1-931956-05-5 |chapter=The Nestorian Schism}}</ref> Since wording of that recension ("who is from the Father and the Son") does not contain any mention of the term "procession" or any of the other particular terms that would describe relations between Father, Son and the Holy Spirit, the previously mentioned claim for the "earliest use" of {{lang|la|Filioque}} clause is not universally accepted by scholars{{Who|date=March 2019}}. Furthermore, another recension that is preserved in the East Syriac sources of the Church of the East contains only the phrase "and in the Holy Spirit".{{sfn|Brock|1985|p=133|ps=, quoted in {{harvtxt|Panicker|2002|pp=58–59}}}}

Various professions of faith confessed the doctrine during the patristic age. The {{lang|la|Fides Damasi}} (380 or 5th century), a profession of faith attributed to Pseudo-Damasus or [[Jerome]], includes a formula of the doctrine.{{sfnm|DH|2012|1loc=n. 71|Kelly|2014|2p=360}}<ref>{{Cite CCC|2.1|193|quote=None of the creeds from the different stages in the Church's life can be considered superseded or irrelevant.}}</ref> The {{lang|la|Symbolum Toletanum I}} (400), a profession of faith legislated by the [[First Council of Toledo|Toledo I synod]], includes a formula of the doctrine.{{sfn|DH|2012|loc=n. 188}} The [[Athanasian Creed]] (5th century), a profession of faith attributed to Pseudo-Athanasius, includes a formula of the doctrine.{{sfnm|PCPCU|1995|DH|2012|2loc=n. 75}}

The generally accepted first found insertion of the term {{lang|la|Filioque}} into the [[Niceno-Constantinopolitan Creed]], in Western Christianity, is in acts of the [[Third Council of Toledo]] (Toledo III) (589),{{sfnm|DH|2012|1p=160|Louth|2007|2p=142|Kelly|2014|3pp=360–362}} nearly two centuries later, but it may be a later interpolation.{{sfnm|DH|2012|1p=160|Kelly|2014|2p=362}}{{efn|An additional profession of faith in the acts of Toledo III, The Profession of Faith of King Reccaredus, included the doctrine but not the term: "{{lang|la|Spiritus aeque Sanctus confitendus a nobis et praedicandus est a Patre et Filio procedere et cum Patre et Filio unius esse substantiae}}."{{sfn|DH|2012|loc=n. 470}}}}