[4] During the first half of his ministry, Rees was instrumental in establishing several new chapels including Park Church (1839), Siloah (1841) and Capel-y-Bryn (1841).

[6] Rees had a remarkable career as publisher of the radical journal, Y Diwygiwr (The Reformer) and as a pioneer in the provision of education.

He was firmly opposed to the established church and conducted a long running feud with the rector of Llanelli, Ebenezer Morris.

A new schoolroom was built early in his pastorate, and in 1875 a group of members were released to form a new church at Tabernacle, towards the cost of which Capel Als contributed a significant sum.

[9] Several hundred members transferred from Capel Als to the new church at Tabernacle, and it was hoped that this would ease the over-crowding at Capel Als, which suffered from poor ventilation and was uncomfortable especially when the chapel was full as it was for the Sunday evening service every week.

Therefore a compromise was reached and the new building maintained many features of the David Rees chapel but it was greatly extended.