It seems that Meurig Fychan was only two years old when his father, Hywel Selau, died. As he was too young to inherit the estate, Meurig was raised by his uncle, Gruffudd Derwas. It seems that Meurig was old enough to inherit Nannau by the second decade of the fifteenth century. In an extent of 1420, Meurig and his uncle, Gruffudd Derwas, are listed as the owners of lands in the vicinity of Nannau..., and their names are recorded as the tenants of Llanfachreth mill in 1444/5. Gruffudd Derwas sold two small holdings to Meurig in 1451, but both Gruffudd and Meurig are recorded as free tenants. In 1452/3 Gruffudd and his nephew, Meurig, are named in connection with Llanfachreth mill.
Some evidence survives that suggests that Meurig was active in the law courts. He is named frequently as a witness in the courts of Caernarfon and Dolgellau... At Dolgellau court in 1452/3 he was named as a witness and in a court case in 1453/4 in Caernarfon Meurig himself is named as the victim... Indeed, many thefts of livestock from Nannau are recorded, indicating how much of an issue this was during the fifteenth century. It is hardly surprising that Guto praises Meurig as one who actively sought to uphold the law.
It is not known when Meurig died, for there is a gap in the Nannau manuscripts between 1460 and 1480. The last reference to him occurs in 1460. According to one source, Meurig died in 1482..., but Pryce... argues that he died soon after 1460. In his elegy for Meurig, Guto clearly states that his patron was buried at Cymer abbey in Llanelltyd near Nannau. 2
Meurig is named among the heirs of a "Wele," of free land, in the township of Nannau, in an extent of Merionethshire taken 7 Henry V, 1419-20, and the "farm," of the mill of Llan Vachreth was granted to both at Michaelmas, 35 Henry VI [1456/7], for four years. Meuric, of Nannau, was foreman of the jury at Caernarvon, 1444, and was living, a very aged man, 2 Henry VII, 1486. 3