Quam Constantinus Dei Gratia Romanorum Imperator,
Ipsius Nepos, Studiose Ac Diligenter ex Variis
Narrationibus Congessit, Ac Scriptori Contribuit
The other two primary sources are "George the Monk" although in two divergent versions, and Symeon (Magister) Logothete.
I give below an overview of Basil's career. I quote a source, Gibbon, which is accessible, not because it's the best source, but because it's free. Note that we must discard the nonsense about Danielis adopting Basil and making him her lover, which is sheer absurdity. Danielis, had Basil join with her own son (adelphiopioinois), and that is the reason why she was so fond of Basil. That Gibbon glosses this in an absurd way, speaks only to Victorian minds, not to the source.
The history of the decline and fall of the Roman Empire, Volume 8 By Edward Gibbon, page 358 : "The genealogy of Basil the Macedonian if it be not the spurious offspring of pride and flattery exhibits a genuine picture of the revolution of the most illustrious families The Arsacides, the rivals of Rome, possessed the sceptre of the East near four hundred years: a younger branch of these Parthian kings continued to reign in Armenia; and their royal descendants survived the partition and servitude of that ancient monarchy. Two of these, Artabanus and Chlienes, escaped or retired to the court of Leo the first: his bounty seated them in a safe and hospitable exile, in the province of Macedonia: Adrianople was their final settlement. During several generations they maintained the dignity of their birth; and their Roman patriotism rejected the tempting offers of the Persian and Arabian powers; who recalled them to their native country. But their splendour was insensibly clouded by time and poverty; and the father of Basil was reduced to a small farm, which he cultivated with his own hands: yet he scorned to disgrace the blood of the Arsacides by a plebeian alliance; his wife, a widow of Adrianople, was pleased to count among her ancestors, the great Constantine; and their royal infant was connected by some dark affinity of lineage or country with the Macedonian Alexander. No sooner was he born, than the cradle of Basil, his family, and his city, were swept away by an inundation of the Bulgarians: he was educated a slave in a foreign land; and in this severe discipline, he acquired the hardiness of body and flexibility of mind which promoted his future elevation. In the age of youth or manhood he shared the deliverance of the Roman captives, who generously broke their fetters, marched through Bulgaria to the shores of the Euxine, defeated two armies of Barbarians, embarked in the ships which had been stationed for their reception, and returned to Constantinople, from whence they were distributed to their respective homes. But the freedom of Basil was naked and destitute: his farm was ruined by the calamities of war: after his father's death, his manual labour, or service, could no longer support a family of orphans; and he resolved to seek a more conspicuous theatre, in which every virtue and every vice may lead to the paths of greatness. The first night of his arrival at Constantinople, without friends or money, the weary pilgrim stept on the steps of the church of St Diomede: he was fed by the casual hospitality of a monk; and was introduced to the service of a cousin and namesake of the emperor Theophilus; who, though himself of a diminutive person, was always followed by a train of tall and handsome domestics. Basil attended his patron to the government of Peloponnesus; eclipsed, by his personal merit, the birth and dignity of Theophilus, and formed an useful connection with a wealthy and charitable matron of Patras. Her spiritual or carnal love embraced the young adventurer, whom she adopted as her son. Danielis presented him with thirty slaves; and the produce of her bounty was expended in the support of his brothers, and the purchase of some large estates in Macedonia. His gratitude or ambition still attached him to the service of Theophilus; and a lucky accident recommended him to the notice of the court. A famous wrestler, in the train of the Bulgarian ambassadors, had defied, at the royal banquet, the boldest and most robust of the Greeks. The strength of Basil was praised; he accepted the challenge; and the Barbarian champion was overthrown at the first onset. A beautiful but vicious horse was condemned to be hamstrung: it was subdued by the dexterity and courage of the servant of Theophilus; and his conqueror was promoted to an honourable rank in the Imperial stables. But it was impossible to obtain the confidence of Michael, without complying with his vices; and his new favourite, the great chamberlain of the palace, was raised and supported by a disgraceful marriage with a royal concubine, and the dishonour of his sister, who succeeded to her place. The public administration had been abandoned to the Caesar Bardas, the brother and enemy of Theodora; but the arts of female influence persuaded Michael to hate and to fear his uncle: he was drawn from Constantinople, under the pretence of a Cretan expedition, and stabbed in the tent of audience, by the sword of the chamberlain, and in the presence of the emperor. About a month after this execution, Basil was invested with the tide of Augustus and the government of the empire.
Jeff Duvall has kindly extracted the details on Basil which are cited in Boswell's "Same Sex Unions in pre-Modern Europe"
Basil’s case is discussed on pages 231-241. His first “union” was with a “certain Nicholas of the church of St. Diomede,” who picked him up off the streets of Constantinople. Basil apparently arrived from the provinces with little more than his looks and the contents of a knapsack and was basically homeless by the time Nicholas found him. Boswell indicates that most of the sources agree that Nicholas and Basil were united through some sort of church ceremony and lived together as “housemate(s) and companion(s).” There seems to be some confusion as to whether or not Nicholas was actually a monk or not, but those sources who identify him as only being a parish cleric in minor orders are the same ones that discuss the church union ceremony. At some point after going through the ceremony with Nicholas, Basil was noticed by a very wealthy man named Theophilos (who seems to have had a reputation for taking an interest in “well-born, good-looking, well-built young men”). Theophilos appointed Basil his chief equerry (protostratorius). While travelling with Theophilos in Greece, Basil met a wealthy widow named Danelis, who “showered him with gifts of gold and dozens of slaves,” in exchange for him (i.e. Basil) agreeing to go through another ceremonial union with her son John. There’s apparently a surviving medieval illustration which shows Basil and John “being united before a cleric in a church.” After he became emperor, Basil seems to have rewarded Nicholas, as well as the church of St. Diomede, with cash gifts, but he went even further with John (according to some sources), who he sent for, gave the title of protospatarius, and “granted intimacy” on “account of their earlier shared life in ceremonial union.” If I remember correctly, Boswell says that all the various accounts containing information on Basil’s same-sex unions were written within a century of the events themselves, so definitely during the reign of the Macedonian Dynasty. Boswell also, of course, discusses Basil’s relationship with Michael III, but as there was no church-approved ceremonial union between the two I’ll not go into the details (of which you’re probably already familiar anyway).
"In most accounts of their relationship Nicholas and Basil are united in a church ceremony. According to one tradition, on the morning after finding him Nicholas 'bathed and dressed Basil and was ceremonially united to him, and kept him as his housemate and companion. (Chronicle of George in Istrin 2:5). Another version is more explicit about the ceremony 'and on the next day he went with him to the baths and changed [his clothes] and going into the church established a formal union with him, and they rejoiced in each other.' (George in Moravcsik p 120) The odd final phrase would probably recall to a Christian Greek reader the biblical "Rejoice with the wife of thy youth." (Prov 5:18)
"Given the wording in the chronicles (one uses adelphiopioinois, another adelphiopiointos) and the fact that the union is accomplished in a church, there can be little doubt that the writers have in mind some form of the ceremony published and translated in this text."