Syriac Christianity produced its theology in verse before it produced it in prose, and the man who fixed that habit was Ephrem, a deacon at Nisibis and later at Edessa, who died in 373. His characteristic form is the madrasha, a stanzaic hymn with a refrain, written to be sung rather than read, and used to argue. Ephrem's hymns take positions against Bardaisan, Marcion and Mani, and they do it in metre, on the reasonable assumption that a congregation will remember what it has sung.
The madrasha is built on syllable count rather than on the long and short quantities of Greek or Latin verse, which means the metre is audible to any speaker and does not require training to follow. Each hymn is headed in the manuscripts by the opening words of another hymn, which names the melody it is to be sung to. There are several dozen such melody models in the surviving headings, and the system assumes that a singer already knows them, because nothing in the manuscript records the tune itself.
That assumption is the tradition's great strength and its great vulnerability. It allowed an enormous body of hymnody to be written down cheaply, without a notation, and carried for sixteen centuries by ear. It also means that where the oral chain broke, as it did in places under Ottoman rule and again in the twentieth century, the words survive with no way back to the music. What is sung now is not, and cannot be shown to be, what Ephrem heard.