In 1843, an article in 'The Cambrian' solicited donations to build what would become Holy Trinity Church in Ystalyfera. Construction began in 1844 and was completed in 1845. The church was consecrated on the 27th May 1845 and opened for public worship, with one service in English in the morning and a second in Welsh in the evening.

In the 28th January 1843 edition of 'The Cambrian' funds were solicited for a Chapel of Ease for Ystalyfera, which would later become Holy Trinity.

A Chapel of Ease is proposed to be built in the Parish of Llanguick, in the county of Glamorgan, under the sanction and approval of the Lord Bishop of the Diocese - St. David's.

With this view, £500 is wanted to erect a plain Building, capable of containing 300 people, almost entirely of the labouring classes, and at the least £500 towards the Endowment Fund. The population of the Parish is 3000, of which the Church will barely seat 350 persons; and it is situated near the lower extremity of the Parish which, in length, is seven miles, and by far the greater part of the Parishioners are located at the extreme upper end. There are, therefore, 2550 agricultural labourers, colliers, and miners, in the Parish without a place of Divine Worship in connection with the Church of England.

Subscriptions are earnestly solicited for the above purpose, and will be thankfully received and deposited at the Glamorganshire Banking Company's, Neath, in the names of the Incumbent and Churchwardens of Llanguick. All communications are requested to be addressed to the Perpetual Curate, the Rev. Wm. Thomas, Kilybebyll, Neath.

The following sums have already been subscribed :-

The Right Rev. the Lord Bishop of the Diocese £20
Her Gracious Majesty the Queen Dowager £20
Mrs Budd, Ystalyfera Iron Works £45
C.R.M. Talbot Esq, M.P., Margam Park £20
R.D. Gough Esq, a site and £20
F.E. Leach Esq, Kilybebyll Place £20
The Perpetual Curate of the Parish £20
A beneficient Lady of the County £20
The Rev. Thomas Gronow £20
Howel Gwyn Esq, Baglan House £5
T. Edw. Thomas Esq, Glanmor £5
Miss Gough, Swansea £5
A. Aylwin Esq £5
Evan Jones Esq, Garth £5
Evan James Esq, Swansea £5
The Rev. J.W. Pugh, Vicar of Llandilo £2
Alexander Cuthbertson Esq £2
Mrs Gwyn, Neath £1
Miss Rees, Gellgron £1

An article in 'The Cambrian' dated 5th October 1844 was headed 'Alltygrug Church' as yet the definitive existence of Ystalyfera had yet to be recognised by the Church. It outlined the work undertaken so far, and the funds raised, but recorded a deficiency in meeting the target despite this generosity.

The foundation stone of this new Church in the Parish of Llanguick, has been lately laid on a site, handsomely given by D. R. Gough Esq., of Yniscedwyn House, the owner of the hamlet; and the building contracted for by Mr. W. Rayner, of Swansea, is progressing satisfactorily with every prospect of being beneficial to the populous parcel of Alltygrug, in which are located the Ystalyfera Iron Works, now extending to great importance. The building has derived much advantage from the support of J. P. Budd (James Palmer) Esq., and the beneficent activity of Mrs. Budd, and the liberal contributions of other kind friends. But notwithstanding these several munificent acts, the funds at the disposal of the Committee are still inadequate for the completion of the edifice. Should this, then, meet the eye of any benevolent person, who might feel desirous of placing the means of religion, through the medium of the Church of England, within the reach of the inhabitants of a large and destitute district, any sum with that view will be gratefully received by the perpetual curate, the Rev William Thomas, Kilybebyll Neath.

The Society for Building additional churches gave a grant of £200 and the Society for the Promotion of Christian Knowledge gave 2 sets of Prayer Books, one in English and one in Welsh.

In the year 1845, 27th May the Church of Holy Trinity Godre'rgraig was consecrated and opened for public worship by the Rev J. W. Pugh, Vicar of Llandeillo with an English Service in the morning and the Rev J. R. Griffiths, Vicar of Cwmamman conducting a service in Welsh in the evening.