Jehovah's Witnesses are modern Arians

"Arius, Waldo, John Wycliffe, and Martin Luther were part of God's organization." (Watchtower, May 15, 1925, p. 149)

Arianism did not exist before the 4th century, but was a development of doctrine, just like Creedal Trinity

"Arianism: Up to this point the Trinitarian debate had taken place entirely in the West. We now move to the East, where the debate became a great controversy. It lasted sixty years, involved the entire eastern church, the western church in part, and occupied the attention of eleven emperors. The long discussion began with Arius, a presbyter in the church in Alexandria. He was a disciple of Lucian, who in turn was a student of Paul of Samosata, bishop of Antioch from 260 to 272. Paul was an Adoptionist (Dynamic Monarchian). He taught that the Logos or Reason of God dwelt in the man Jesus. This Logos had also been in Moses and in the prophets; in Jesus, however, it was present in much larger measure. As a result, he was united with God in a relationship of love as no other man had been. Therefore, God "adopted" Jesus after his crucifixion and resurrection and gave him a sort of deity. Three synods in Antioch dealt with Paul's teaching, and the third one (in 269) condemned and excommunicated Paul. These views deeply influenced Arius. Like the western Adoptionists, he was concerned about the unity of God. Therefore, he taught that the Father alone is without a beginning. The Son (or Logos) had a beginning; God created the Logos in order that he might create the world. Since the Logos was the first and highest of all created beings, Arius was willing to call the Logos God. But this was only a manner of speaking. The Logos was a creature. And God himself could not create the material world; indeed, Arius considered God so far removed from men that it was impossible to know him or to have fellowship with him. Arius was thoroughly Greek in his conception of God. Arius' view of Christ was much inferior to that of either Theodotus in the West or of Paul of Samosata in the East. In their view, the man Jesus whom God adopted was fully and truly human. Not so the Jesus of Arius. In his teaching, Jesus had a human body but not a human soul. The Logos took the place of the human soul in Jesus. He was therefore a creature who was neither God nor man. He was not God because the Logos that was in him was created; he was not man because he did not have a soul. Moreover, the Logos was subject to change: he could become a sinner. Such was the teaching which Arius began to set forth in about 311. Alexander, the Catholic bishop of Alexandria, convened synods which condemned his views, and he was forced to leave Alexandria. Nevertheless, he gained a great following. There were three reasons for this:' a. His views seemed to protect the unity of God against the danger of polytheism. b. They satisfied the deep-rooted Greek idea that God cannot be the creator of the material universe. c. They gave high honor to the Son or Logos of God and even declared him to be God. The controversy spread to all parts-of the East. Theologians, monks, and church leaders took sides in the debate. The common people did, not understand the issues, but nevertheless they aligned themselves with this or that view."   (A Short History of the Early Church, Harry R. Boer, p113)

Arianism influenced by Neoplatonic philosophy

1. "Arianism is a union of adoptionism with the Origenistic-Neo-Platonic doctrine of the subordinate Logos which is the spiritual principle of the world, carried out by means of the resources of the Aristotelian dialectics" (Outlines of the History of Dogma, Adolf Harnack, p251)
2. "Arianism: ... Arius was willing to call the Logos God. But this was only a manner of speaking. The Logos was a creature. And God himself could not create the material world; indeed, Arius considered God so far removed from men that it was impossible to know him or to have fellowship with him. Arius was thoroughly Greek in his conception of God. Arius' view of Christ was much inferior to that of either Theodotus in the West or of Paul of Samosata in the East. ... They satisfied the deep-rooted Greek idea that God cannot be the creator of the material universe. (A Short History of the Early Church, Harry R. Boer, p113)
3. From the outset, the controversy between both parties [Arius & Nicenes] took place upon the common basis of the Neoplatonic concept of substance, which was foreign to the New Testament itself. It is no wonder that the continuation of the dispute on the basis of the metaphysics of substance likewise led to concepts that have no foundation in the New Testament such as the question of the sameness of essence (homoousia) or similarity of essence (homoiousia) of the divine persons. (Encyclopedia Britannica, 1979, Christianity, Vol. 4, p.485)

The Semi-Arians

The Semi-Arians, who thought it enough to admit the Son's likeness to the Father, but would not allow the second Person to be equal to or consubstantial with the first, were driven by the force of logic, to make the Holy Ghost a creature. (A Catholic Dictionary, William E. Addis & Thomas Arnold, 1960, p 822-830)

Arianism was rejected because it is polytheistic

1. According to its opponents, especially Athanasius, Arius' teaching reduced the son to a demigod, reintroduced polytheism (since worship of the Son was not abandoned), and undermined the Christian concept of redemption since only he who was truly God could be deemed to have reconciled man to the God-head. (Encyclopedia Britannica, 1979, Arianism, Vol. I, p.509)
2. Thus Arius argued that a Son, who was, in like sense as God the Father, 'eternal' and consequently god-like, would no more be the Son, but the Brother of the Father. But now many Arians compromised to the effect that the Logos-Son was indeed not true God (but a high angelic-being), but that he was called God, this honour having been graciously bestowed upon him. With this God 'in the second place' the Arians would surely have raised no stir and certainly no 'Arian' controversy in the time of Justin, who, being heir to the Angel-Christology, taught practically the same thing. However, now they were convicted inexorably of polytheism and of deifying the creature. (The Formation of Christian Dogma, An Historical Study of its Problems; Martin Werner, p160, Werner is a modernist who also advocates Angel Christology commenting on Arianism)
3. "only as cosmologians are the Arians monotheists; as theologians and in religion they are polytheists; finally in the background lie deep contradictions: A Son who is no Son, a Logos which is no Logos, a monotheism which does not exclude polytheism, two or three who are to be adored, while really only one differs from the creatures, an indefinable being who only becomes God in becoming man, and who is neither God nor man." (Outlines of the History of Dogma, Adolf Harnack, p251)
4. "now they (Arians) were convicted inexorably of polytheism and of deifying the creature." (The Formation of Christian Dogma, An Historical Study of its Problems; Martin Werner, p160, Werner is a modernist who also advocates Angel Christology commenting on Arianism)
5. The basic concern of Arius was and remained disputing the oneness of essence of the Son and the Holy Spirit with God the Father, in order to preserve the oneness of God. The Son, thus, became a "second God, under God the Father"-i.e., he is God only in a figurative sense, for he belongs on the side of the creatures, even if at their highest summit. Here Arius joined an older tradition of Christology, which had already played a role in Rome in the early 2nd century-namely, the so-called angel-Christology. The descent of the Son to Earth was understood as the descent to Earth of the highest prince of the angels, who became man in Jesus Christ; he is to some extent identified with the angel prince Michael. In the old angel-Christology the concern is already expressed to preserve the oneness of God, the inviolable distinguishing mark of the Jewish and Christian faiths over against all paganism. The Son is not himself God, but as the highest of the created spiritual beings he is moved as close as possible to God. Arius joined this tradition with the same aim-i.e., defending the idea of the oneness of the Christian concept of God against all reproaches that Christianity introduces a new, more sublime form of polytheism. This attempt to save the oneness of God led, however, to an awkward consequence. For Jesus Christ, as the divine Logos become man, moves thereby to the side of the creatures-i.e., to the side of the created world that needs redemption. How, then, should such a Christ, himself a part of the creation, be able to achieve the redemption of the world? On the whole, the Christian Church rejected, as an unhappy attack upon the reality of redemption, such a formal attempt at saving the oneness of God as was undertaken by Arius. ... The redemption of man from sin and death is only then guaranteed if Christ is total God and total man (Encyclopedia Britannica, 1979, Christianity, Vol. 4, p.485)
6. "Arianism: Before Nicaea, Christian theology was almost universally subordinationist. Theology almost universally taught that the Son was subordinate to the Father, but Arius expressed this kind of Christology in a provocative way. ... The slogan of Arius and his allies soon came to be this: "There was when he was not." (Gods and the One God, Robert M. Grant, p160)

Arius and Jw use same line of reasoning:

• "A characteristic exegetical ploy of the Arians was to invoke texts in the interests of what might be called 'reductionism', that is to say they would try to reduce the value of the titles given (or thought to be given) to Christ in the Bible by showing that they were also applied in the Bible to quite ordinary people or things. Asterius played this game extensively in a well-known passage: "'Like" (the Son to the Father): well, it is written about us that "man is the image and is the glory of God" (1 Cor 11:7); as for (the Son existing) ."always", it is written "while we live we are always ..." (2 Cor 4:11); as for (the Son being) "in him", (it is written) that "in him we live and move and have our being" (Acts 17:28); as for (the Son being) "unchanging", it is written "nothing shall separate us from the love of Christ" (Rom 8:35). On the subject of (the Son being) the power (of God), (it is written) that the caterpillar and the locust are called the "power" even the "great power" of God (Joel 2:25 LXX), and the same is often said about the people, for instance, "all the power of the Lord went out from the land of Egypt" (Ex. 12:44 LXX), and there are other heavenly powers for it says "the Lord of the powers is with us, the God of Jacob is our champion"' (Ps 46 (45):8). Greg and Groh, (Early Arianism, p107-108) give a list of texts used by Arians to reduce the significance of the Son's partaking in God. (R. P. C. Hanson, The Search for the Christian Doctrine of God, The Arian controversy 318-381, p838)
• In the New Testament affirmations about the Son were largely functional and soteriological, and stressed what the Son is to us. Arians willingly recited these affirmations but read into them their own meaning. To preclude this Arian abuse of the Scripture affirmations Nicea transposed these Biblical affirmations into ontological formulas, and gathered the multiplicity of scriptural affirmations, titles, symbols, images, and predicates about the Son into a single affirmation that the Son is not made but born of the Father, true God from true God, and consubstantial with the Father. (The Triune God, Edmund J. Fortman, p 66-70)

Final defeat of Arianism

1. "The Church had to face up to the Arian question and go on record for or against the Arian answer. It did this at Nicea. Though there may be doubt about the understanding of 'consubstantial' at Nicea, there can be no doubt about the historical and dogmatic importance of the Council itself. For there the Church definitively rejected the answer that Arius gave to the question he put: Is the Son God or creature? The Council firmly rejected Arius' contention that the Son was a creature, not eternal, and made out of nothing." (The Triune God, Edmund J. Fortman, p 66-70)
2. "Arianism was doomed. It had indeed, with its reference to Scriptures and the old tradition of the Church, good arguments at its disposal. But it allowed itself in the course of the conflict to be misled into compromises with its opponent, which landed it into difficulties, of which advantage was effectively taken. Compromise finally went so far that the Arians could be charged with polytheism. Before Arius, as we have seen, the Angel-Christology had also already made concessions to the new deification of Christ. But, by the time of Arius, in the Church one had become sensitive about the charge of polytheism. For Modalism had criticised the accepted Trinitarian doctrine of the Church as a doctrine of three gods. The Church was, therefore, prepared to clamber out of the former incompleteness of its doctrine of the divinity of Christ and to follow Modalism, in so far as this was compatible with its essential position. But Arianism now on occasions itself slid, by its compromises, into a similar incompleteness, although the maintenance of the strong original monotheism of Deut. vi, 4/Mk. xii, 29 represented its own initial position. In this respect it had hitherto been no less sensitive than Modalism. Thus Arius argued that a Son, who was, in like sense as God the Father, 'eternal' and consequently god-like, would no more be the Son, but the Brother of the Father. But now many Arians compromised to the effect that the Logos-Son was indeed not true God (but a high angelic-being), but that he was called God, this honour having been graciously bestowed upon him. With this God 'in the second place' the Arians would surely have raised no stir and certainly no 'Arian' controversy in the time of Justin, who, being heir to the Angel-Christology, taught practically the same thing. However, now they were convicted inexorably of polytheism and of deifying the creature." (The Formation of Christian Dogma, An Historical Study of its Problems; Martin Werner, p160, Werner is a modernist who also advocates Angel Christology commenting on Arianism)