c. 535–536
Greek
Only-Begotten Son
Ho Monogenes
Attributed to Justinian I · c. 482 – 565
A short hymn, sung at every Byzantine liturgy since, compressing the whole Chalcedonian settlement into one sentence: the immortal Word became flesh of the Theotokos, was crucified, and trampled down death by death, being one of the Holy Trinity.