He is noted for developing the awdl and englyn.

At the Aberffraw eisteddfod of 1849, he won the bardic chair for an awdl on the Creation.

An 'awdl' is a long poem written in Welsh language in one of the twenty-four strict metres, using cynghanedd.

Most of the information we have about Cadfan is from the awdl by Llywelyn the Bard in the 12th century.

In 1849 at the Aberffraw eisteddfod he rose to his feet to contest the adjudication and defend his defeated awdl.

The various forms of cynghanedd show up in the definitions of all formal Welsh verse forms, such as the awdl and cerdd dafod.

In 1966 he won the Chair at the National Eisteddfod with an awdl entitled "Cynhaeaf" (English: Harvest).

It is for this occasion that Gwynfardd Brycheiniog's awdl in honour of the Lord Rhys is thought to have been composed.

Amongst Einion's surviving poems is an awdl sung is praise of Sir Rhys ap Gruffudd.

In 1824, Williams' Baron Richards was judged to be the best at Awdl the Cymreigyddion eisteddfod in Caernarvon.

He spent most of his furlough working on the awdl Yr Arwr ("The Hero"), his submission for the National Eisteddfod.

Hywel Foel's only surviving work is an awdl which laments the capture and imprisonment of Owain ap Gruffudd at Dolbadarn Castle.

An awdl by Dafydd Benfras hails 'Llywelyn' as y daroganwr ("son of the prophecy"; Y Mab Darogan).

He composed a notable awdl farwnad (elegy) on the death of his patron and a marwysgafn on his own approaching end, noted for its intensity and depth of feeling.

Another awdl to Llywelyn the Great by Llywarch ap Llywelyn (Prydydd y Moch) declares that he is the prince who will "fulfil the ancient prophecies".

Possibly the best-known is in 'Yr Awdl Fraith', a long poem or awdl attributed to Taliesin, and one of the most popular of the period.

The Hymn to the Virgin was written by Ieuan at Oxford in about 1470 and uses a Welsh poetic form, the awdl, and Welsh orthography; for example:

Welsh chroniclers have made but scanty references to Gerald; no bard has ever yet sung an Awdl or a Pryddest in honour of him who fought for the "honour of Wales."

The text of this awdl is preserved in the Hendregadredd manuscript and is noted for being one of the earliest direct references to Snowdonia (Welsh: Eryri) in Welsh poetry.

Wedyn mae yna grochenwaith yna sydd wedi defnyddio barddoniaeth Llyr Gwyn Lewis, yr awdl enillodd gadair yr Urdd iddo yn 2010.

Probably the most famous awdl is the apocalyptic elegy composed by Gruffudd ab yr Ynad Coch on the occasion of the death in 1282 of Llywelyn ap Gruffudd (see above).

A new bardic chair is specially designed and made for each eisteddfod and is awarded to the winning entrant in the competition for the Awdl, poetry written in a strict metre form known as cynghanedd.

Facing what may be his last chance to win the Eisteddfod, Ellis pleads with his platoon commander to send his awdl Yr Arwr (The Hero) via the Army Postal Service.

In 1916 he took second place at the Aberystwyth National Eisteddfod with Ystrad Fflur, an awdl written in honour of Strata Florida, the medieval Cistercian abbey ruins in Ceredigion.

Such poems are considered among the finest work that a poet can aim to produce, and prizes are given at eisteddfodau for the best awdl, including the most lauded prize, that of the Chair at the National Eisteddfod of Wales, held every year in August.