Cellach of Armagh or Celsus or Celestinus (1080–1129) was Archbishop of Armagh and an important contributor to the reform of the Irish church in the twelfth century. He is venerated in the Roman Catholic Church as Saint Cellach. Though a member of the laicized ecclesiastical dynasty of Clann Sínaig, he took holy vows and gained priestly ordination. This put an end to the anomalous state of affairs, in effect since 966, whereby the supreme head of the Irish Church had been a layman. Following the Synod of Ráith Bressail, in which a diocesan structure for Ireland was established, he became the first metropolitan primate of all Ireland.
Cellach was the son of Áed mac Máele Ísu meic Amalgada of the Clann Sínnaig. Áed had been abbot of Armagh and Coarb Pátraic ("heir" or "successor" of Saint Patrick; head of the church of Armagh) from 1074 to 1091. The Clann Sínaig, of the Uí Echdach sept of the Airthir in Airgialla, had monopolized the office of abbot of Armagh since 966. In later historiography Clann Sínaig has been associated with the type of secularisation that made a church reform necessary, described by Marie Térèse Flanagan as an "hereditarily entrenched laicized ecclesiastical dynasty" and even less flattering denounced by Bernard of Clairvaux as that "generatio mala et adultera".
According to the Christian father Origen, Celsus (/ˈsɛlsəs/; Greek: Κέλσος) was a 2nd-century Greek philosopher and opponent of Early Christianity. He is known for his literary work, The True Word (also Account, Doctrine or Discourse; Greek: Λόγος Ἀληθής), which survives exclusively in Origen's quotations from it in Contra Celsum. This work, c. 177 is the earliest known comprehensive attack on Christianity.
According to Origen, Celsus was the author of an anti-Christian work titled The True Word (Alēthēs logos). This work was lost, but we have Origen's account of it in his writings. It was during the reign of Philip the Arab that Origen received this work for rebuttal. Origen's refutation of The True Word contained its text, interwoven with Origen's replies. Origen's work has survived and thereby preserved Celsus' work with it.
Celsus seems to have been interested in Ancient Egyptian religion, and he seemed to know of Jewish logos-theology, both of which suggest The True Word was composed in Alexandria. Celsus wrote at a time when Christianity was being persecuted and when there seems to have been more than one emperor.
Titus Cornelius Celsus, was a fictionalRoman usurper, who supposedly rebelled against Gallienus. He was one of the so-called Thirty Tyrants enumerated by Trebellius Pollio.
According to the Historia Augusta, in the twelfth year of Gallienus' reign (265), when usurpers were springing up in every quarter of the Roman world, a certain Celsus, who had never risen higher in the service of the state than the rank of a military tribune, living quietly on his lands in Africa, in no way remarkable except as a man of upright life and commanding person, was suddenly proclaimed emperor by Vibius Passienus, proconsul of the province, and Fabius Pomponianus, general of the Libyan frontier. So sudden was the movement, that the appropriate trappings of dignity had not been provided, and the hands of Galliena, a cousin it is said of the lawful monarch, invested the new prince with a robe snatched from the statue of a goddess.
The downfall of Celsus was not less rapid than his elevation: he was slain on the seventh day, his body was devoured by dogs, and the loyal inhabitants of Sicca testified their devotion to the reigning sovereign by devising an insult to the memory of his rival unheard-of before that time. The effigy of the traitor was raised high upon a cross, round which the rabble danced in triumph.
Celsus may refer to: