I have before given some examples of writing a name upside down as a kind of curse (cf. here). This is most often done with the name of Satan, but also for those considered heretics. We know the practice from Syriac, but also from Arabic, at least in Garšūnī. (I wonder about other language traditions, Christian and otherwise; I will be glad to hear of examples from other manuscript traditions that have escaped me.) The image below is from CFMM 301, an early 20th-cent. manuscript (completed at Dayr Al-Zaʿfarān on Aug. 19, 1912) with some hagiographic works and the Tale of Aḥiqar, this part from a version of the Story of Mor Gabriel (pp. 82-150 of the manuscript).
Here is a transliteration (with vowels added, of course) and translation:
wa-māta Anasṭūs al-malik al-muʾmin allaḏī banā al-haykal wa-kāna mawtuhu sana 829 y[ūnānīya] allāh yunīḥu nafsahu wa-yanfaʿunā bi-ṣalātihi amīn. wa-baʿdahu Yūsṭānīnūs al-kāfir bi-l-masīḥ wa-tabaʿa sūnudūs al-muḫālifīn wa-ḍṭahad al-muʾminīn wa-aḏalla al-masīḥīyīn ǧiddan
Anastasius, the believing emperor, who had built the sanctuary, died; his death was in the year 829 Anno Graecorum [= 518 CE]. May God grant rest to his soul and benefit us with his prayer! After him [came] Yūsṭānīnūs, the denier of Christ, and he followed the synod of the transgressors [i.e. the Council of Chalcedon], oppressed the believers and greatly degraded the Christians.
- haykal I have rendered “sanctuary.” This probably refers to the church and prayer hall commissioned by Anastasius in 512.
- allāh yunīḥu nafsahu is a calque of Syriac alāhā nniḥ napšēh.
- (i)ḍṭahad must be the correct reading, despite the dot in the ṭet.
The first emperor mentioned here is Anastasius I, not a supporter of Chalcedon and not unfriendly to the adherents of Miaphysite doctrine. The second emperor referred to, whose name is written inverted, is either 1) Justin, who, in fact, followed Anastasius, or 2) Justinian, who followed Justin. The form of the name as written here looks more like that of the latter than of the former, but neither supported the Miaphysites and might be unexpectedly cursed by graphic inversion, while Anastasius is blessed. (Incidentally the name of Satan is not written upside down in this text!) On the next folio after this one, the expulsions of Severus, Philoxenus, Anthimus, and Theodosius are mentioned, and at least some of them were deposed before Justinian’s rule began in 527, but others closer to or in 536.
The ins and outs of the Council of Chalcedon and its aftermath are covered in any good volume that treats Late Antiquity and church history in the fifth and sixth centuries. For other topics in play here, note the following:
Aydin, Eliyo. Das Leben des heiligen Gabriel. The Life of Saint Gabriel. Tašʿitā d-qaddišā Mār(y) Gabriʾel. Bar Hebraeus Verlag, 2009. [Vocalized Syriac text, GT, and ET.]
Hunt, Lucy-Anne. “Eastern Christian Iconographic and Architectural Traditions: Oriental Orthodox,” in Ken Parry, ed., The Blackwell Companion to Eastern Christianity. Oxford, 2007. 388-419 (esp. 390).
Palmer, A.N. “Gabriel, Monastery of Mor,” in GEDSH, 167-169.