The Wesleyan Methodists constructed Gurnos Chapel, Ystalyfera in 1839-40 but sold it to the Congregationalists in 1858. Seion Methodist Chapel was built in 1862 in the Sub-Classical style with a gable entry plan. It was located on Milborough Road, Ystalyfera, but has since been demolished.

From the Labour Voice Saturday 29th April 1922:-

REV LLEW JONES

Deep regret will be felt by a large circle at Ystalyfera on learning of the death which occurred at Machynlleth on Easter Monday of the Rev Llew Jones, Wesleyan Minister late of Ystalyfera. The rev gentleman was cut off in the prime of life being only 54 years of age. He had been ill for a long period.
It is many years since the rev gentleman was stationed at Ystalyfera. He had been in charge of churches at Hirwaun and Aberdare and was about to return to Aberdare in answer to a second "call" at the time of his death.
The funeral took place at Machynlleth on Thursday of last week.
The deceased leaves a widow and 1 daughter. He was a brother of Mrs G Griffiths, wife of Mr G Griffiths, manager of Lloyds Bank Ystalyfera, and Mrs Hughes, wife of the Rev Hugh Hughes.

From the Labour Voice Saturday January 31st 1925:-

LOCAL WESLEYAN PREACHER
Death of Mr William Evans

The death took place on Friday morning of Mr William Evans, Brynogwen, Alltygrug Rd, Ystalyfera. Although Mr Evans had suffered considerably from ill health during the last 10 years, especially from a heart affection and asthma (which he had fought with rare courage and determination) the end came rather suddenly. He was taken seriously ill on the previous Monday, and he sank gradually and passed away as stated.

In Mr Evans Ystalyfera loses one of its most respected citizens. He was very well known especially in religious circles, throughout West Wales as a recognised Wesleyan local preacher. He had carried out the duties of this position very faithfully and conscientiously for about 40 years. For the greater part of his life he had followed the occupation of a miner in many local collieries and was for some time a check-weigher. During the last 10 or 12 years, however, he had been interested as part-proprietor in various local colliery enterprises, which unfortunately did not prove very successful.

But the real life of Mr William Evans was spent in the little chapel which is known as Seion Wesleyan Chapel, Ystalyfera, and in the pulpits of Welsh Wesleyan churches in the Swansea and Neath circuits. Any account of his career which neglected to emphasise his intensely religious life would be not only hopelessly inadequate but actually misleading. His whole life was built round his religion. He had few outside interests. His social and intellectual life and everything else had religion as their centre. It was not zeal without knowledge, either, for he possessed what is not often found amongst the laity, a fairly adequate knowledge of what has been written and thought on the philosophical, scientific and theological aspects of religion. And for a man who had had no educational advantages in his youth, he had achieved a good deal and had attained to a degree of culture which was exceedingly creditable, and not often found amongst working people. In the theological discussions which he was so fond of initiating, he always proved himself an original and independent thinker, who no names however eminent, would terrify. His mental and religious outlook may be gauged in a way when it is stated that the two thinkers and writers for whom perhaps he had the greatest admiration were John Wesley and Sir Oliver Lodge. It is needless to add that his character was such as might be expected - without blemish and without reproach. Straight and conscientious in all his dealings with other people, he yet had a tender heart and a good lovable nature.

He is survived by his widow and two children, namely: Mrs Roberts, Cwmtwrch, and Mr William Arthur Evans, Commercial Street Ystalyfera.

The funeral took place on Tuesday afternoon at Alltygrug New Cemetery. At the graveside the reverends W A Evans, BA, curate, E D Thomas, superintendant of Circuit, and Llewelyn Morgan, Pontardawe, officiated.

The Reverend E D Thomas, in a short address, referred to the excellent qualities of the deceased. Although Mr Evans had been unable owing to indisposition to preach often during the last 5 years, the speaker had heard much of his sermons, his great earnestness and his consecration to the cause of religion. Mr Evans was compelled to retire through illness.

The Reverend Llew Morgan, Pontardawe, said during the last few years when he was unable to preach as of old, he had been buying or borrowing the latest books on various aspects of religion, and especially those which treated of the relations between religion and philosophy, and religion and science. May God raise more men of this type.

The chief mourners were Mr William Arthurs Evans, son, Mr John Roberts, son-in-law...

The South Wales Voice of 3rd January 1958 records the death of Brinley Thomas, who was a member of Seion Wesleyan Chapel, and a well respected lay preacher in the area:-

MR BRINLEY THOMAS, M.A.

The death has taken place after a short illness of Mr Brinley Thomas, M.A., Is-yr-allt, Alltygrug, Ystalyfera, at Morriston Hospital.
Mr Thomas was 67 years of age and a native of the district. He was, in his young days, a well-known athlete. He was educated at Pantteg School and Ystalyfera Intermediate School.
After gaining his M.A. at Bangor University, he served as an officer in the Royal Artillery in France during the 1914-18 war.
On demobilisation he was appointed to the staff of Aldershot Grammar School.
He retired four years ago to live at Ystalyfera, the place he loved so much. He was a member of Seion Wesleyan Chapel.
A contemporary of the late Hedd Wyn, of the famous "Gadair Ddu" episode, Mr Thomas was a Welsh poet of National standard.
A son of the late Mr W.D. Thomas, a former precentor of Pantteg Chapel, and first conductor of the Ystalyfera Public Band, he too, was a very fine musician. He had conducted choirs and several festivals while at Aldershot, and rehearsals of many gymanfaoedd ganu since his return to Ystalyfera.
In great demand as a lay preacher for many years, he preached over a wide area after joining Seion Chapel.
Besides his wife Caroline, he leaves two daughters, Anne, who is at home; Naomi, a classic mistress at Gloucester High School; and a son, Mr Emyr Thomas, deputy Town Clerk at West Bromwich. He is also survived by an only brother, Mr Emlyn Thomas of 99 Heol-y-Farteg, Ystalyfera.
The funeral, private, is at 2:30pm today, Friday January 3rd. Friends are requested to meet at Godre'rgraig cemetery for the interment.