In the course of a bardic disputation early in Cynddelw 's career ( Myv. Arch. , 154a), he was reminded that he had sprung from no family of poets , and although his opponent, Seisyll Bryffwrch (q.v.) , was concerned in minimizing his achievements, he refers to him as ‘Cynddelw the big, giant of gatherings’; hence it is to be presumed that he was called ‘Mawr’ in the first place on account of his size. He had at least one son, named Dygynnelw , who was killed in battle ( Myv. Arch. , 185a).

Cynddelw was appointed leading poet to the court of Madog ap Maredudd , prince of Powys (d. 1160 ) (q.v.) . His two best extant poems resulting from his connection with Madog 's court are ‘ In praise of Eve ,’ who was the prince's daughter, and the fine series of eighteen englynion in which he laments the death of Madog and his son Llywelyn , with whom was buried the unity of Powys . Cynddelw then turned to sing the praises of Owain Gwynedd (q.v.) , and his poetic gifts are seen at their height in the ‘ Elegy to Owain ,’ 1170 . Henceforward, and until the end of the century, he sang to a number of the leading princes of Gwynedd , Powys , and Deheubarth , and in this respect he is the earliest poet known to have taken the whole of Wales as his field. He also sang awdlau to God, and his ‘ Song to Tysilio ’ is largely in praise of Meifod . His only other extant religious poem is the ‘ Deathbed song .’ His poetry is mainly characterized by a quality described by W. J. Gruffydd as ‘primeval starkness.’

The last of his compositions which can be dated precisely is the series of englynion to Llywelyn ap Iorwerth ( Myv. Arch. , 189b), in which the rise of that prince (q.v.) is described as far as his capture of Mold in Jan. 1199 . (His authorship of the later englynion entitled the ‘ Circuit of Llywelyn ’ is very dubious.) Part of his ‘ Deathbed song ’ is found in the ‘ Black Book of Carmarthen ,’ and a little of his work also appears in Pen. MS. 3 , which also belongs to the first half of the 13th cent. Most of Cynddelw 's extant work is found in the Hendregadredd manuscript , a considerable part in the ‘ Red Book of Hergest ,’ and all which has survived has been collected together in Myv. Arch.