A clue to the "Nicolaitanism" that Christ hates so vehemently (Revelation 2:6,15) is the lone occurrence of the name "Nicolas" here. It appears in the section describing the dispute between the Hebrews and the Hellenists over the neglect of the latter's widows. To solve this problem, the church chooses seven deacons to oversee the physical work of distributing food to the needy brethren, and one of these is "Nicolas, a proselyte from Antioch."
Again, this description provides the most meager of hints about the man but enough to propose some conclusions. Nicolas is a Hellenist, meaning primarily that he spoke Greek, but probably also suggesting that he possessed a Greek education. As such, "they [the 'Hellenists'] maintained a more liberal outlook than the 'Hebrews,' including the apostles" (F.F. Bruce, New Testament History, p. 219), especially regarding keeping the law. This "liberal outlook" toward the law later formed the heart of the debate at the Council of Jerusalem in AD 49 (Acts 15).
That Luke calls him a proselyte tells us that he is a Gentile who converted to Judaism before his calling to Christianity. Becoming a proselyte required a Gentile to keep Jewish law in its entirety, undergo circumcision, be baptized, and make a special sacrifice at the Temple. This rigorous process indicates that Nicolas must also have been quite devout and dedicated in his beliefs. The church's choice of him as one of the first deacons reveals he likely possessed standout natural abilities and leadership qualities, as well as fulfilling the apostles' qualifications of being "of good reputation, full of the Holy Spirit and wisdom" (Acts 6:3).
The last tidbit of information is that he is from Antioch, the largest city and capital of the Roman province of Syria. The city's residents—Greeks, Macedonians, Syrians, Jews, Romans, and others—brought to it their own languages, cultures, philosophies, and religions. F.F. Bruce writes, "Its cosmopolitan population and material wealth provided an apt setting for cultural exchange and religious syncretism" (ibid., p. 264). This urban, multicultural, religious mélange formed Nicolas' background.
Unfortunately, it is in the context of syncretism that Nicolas is last mentioned in the post-biblical, historical record. Both Irenaeus (Against Heresies 1.26.3; 3.10.6) and Clement of Alexandria (Miscellanies, 3.4.25f) consider Nicolas of Antioch to be the founder of the Gnostic sect known as the Nicolaitans. Another early writer, Hippolytus, adds that Nicolas "departed from sound doctrine, and was in the habit of inculcating indifferency of both life and food" (Refutation of All Heresies, 7.24), meaning he taught the Gnostic belief of the irrelevance of physical things. This reinforces Clement's claim that Nicolas became an ascetic and that his followers later perverted his teachings to encompass idolatry and immorality (2.20.12), becoming what we know as Nicolaitans.
From this information, we can hypothesize the evolution of Nicolaitanism. Roman church historian Eusebius writes that Nicolas himself was a moral man (Ecclesiastical History, 3.29). Though sincere and devout, he came to believe that the only way to grow spiritually was to consider his body and its desires as unimportant. In this way, he could ignore them in favor of spiritual pursuits. His fundamental doctrine appears to have been "the flesh must be treated with contempt."
Over the years, however, this teaching took on a more Gnostic spin: Since the flesh is unimportant, even contemptible, what one does in the flesh is of no consequence. Spiritual life, growth, and ultimately salvation occur in the soul, and since God is spirit, He has no regard for the flesh. Therefore, Nicolaitans reasoned, what does it matter if one satisfies the flesh's desires? At some point in its early history, then, Nicolaitanism evolved from an ascetic philosophy to a licentious one—one that Christ says He hates.