Eudaf had a son or nephew Cynan or Conan, chieftain of a small territory called Meriadog, in the present Denbighshire, where it is still known by its ancient name. He was related to Elen, the daughter of Eudaf, who married Magnus Maximus. See Desendents of Bran ap Llyr 75 & 76
Cynan accompanied his brother-in-law Magnus Maximus in command of the native British troops and levies, which with two Roman legions 14,000 strong amounted to 40,000 men, and this, allowing for exaggeration, must have been a strong force. After the defeat of Gratian, Cynan and his troops were settled in Armorica by Maximus. Another and more probable account is, that after the defeat of Maximus the survivors of his British allies were sent by Theodosius to settle amid their countrymen in Armorica under the government of Cynan as a Roman magistrate, who, though a subordinate ruler for a time, was ancestor of a long line of independent kings of Armorica.
Some time before his death, Cynan became independent of Roman control. Daru, in his "History of Bretaigne" dates this event at A.D. 410. In the year 416, Exuperantius, Prefect of Gaul, was sent into Armorica to reduce the Britons to obedience, but he failed to acconmplish this mission. Up to the year 418, Germanus, afterwards Bishop of Auxerre, was Dux or Roman governor of Armorica and the Nervian districts; after his consecration as bishop, on the 7th of July in 418, he ceased to be a civil ruler; and it is not at all improbable that, through his influence with Theodosius, the Britons, under Cynan as their king, were left independent; for in the next year, 419, the Britons of Armorica were treated as allies by the Romans. Cynan died at Nantes, the seat of his government, in 420; he left issue two sons: Congar, of whom there is no further record; Urban, Urien or Erbyn, who died four years before his father. As his decease was contemporary with the invasion of Exuperantius, it is not improbable that Urban fell in defence of his country.
Daru, the Historian of Bretaigne, vol. i. p. 64, states, on the authority of Abbe Gallet, that Cynan was twice married, and that his second wife was a sister of St. Patrick; that is Sen, or Old Patrick Irish authorities state that Darerca, St. Patrick's sister, was married to a man of the British nation called Conis, Cone, and Conitius. Considering the numerous aliases connected with the names of the reguli of the Britons oif Armorica, the Irish form of this name may very well represent Cynan. Conitius was the father of six or more sons; the eldest was St. Mel, Bishop of Ardagh, in Ireland, who died A. d. 487; he was born probably about the year 404, Another son, named after his father, Conitius, Conit, Conu, and Cone, is spoken of in the "Tripartite Life of St. Patrick," part II, capt. xviii., xix., as a "ceard" or worker in metals. He was a bishop; his church was at Tellach-na-Cloch, now Tullanaroch, in the parish of Kilcolman, in Mayo. The period of these ecclesiastics synchronizes with the time of Cynan Meriadog, who died AD. 420. There are evidently some germs of truth underlying the assertions of Gallet and the ancient Irish authorities: undoubted and well-sustained facts of a like kind, in other instances in connexion with Armorican families, give a strong appearance of reality to these old historic authorities. (See Family and Kindred of St Patrick).
Cynan Merladog, his Descendants Kings of Bretagne, continued intercourse with the mother-country Britain along with the Armorican Saints and Ecclesiastics who were very connected with Britain and Ireland in the fifth and sixth centuries.
Meriadog still surviyes in the name of a small township Cevn Meriadog, in the parish of St. Asaph, in the Hundred of Isdulan Denbighshire, on the left bank of the River Elwy, where there are some caves in the limestone cliffs over-hanging the river. The is a hill forest named Meriadog and a fort called Bedd-y-cawr on the west bank. In early times, Meriadog comprised a large territory, of which Cynan was regulus.
Currently there is the false belief that Meriadog was founded by St. Mériadek, a saint described by Gilbert H. Doble, in "The Saints of Cornwall" (1934). Also, the historians of Bretaigne are quite mistaken in interpretating Meriadog as they write it, "the great king" as it is not a Hebrew word, Meriadog is only the affixed name showing where Cynan came from. Examples of this are quite common i.e. Brockwell, Ysgathrog; i. e. Skatrog, a place in Denbighshire, Emrhys, Lyddaw, i. e. of Letavia; Constans or Cystennangonew, i.e. Cerniw, an old place in Monmouth.