Complex sentence: As a pioneer of congregational music in the Merthyr area he was the first choirmaster to substitute women for men in the singing of treble parts, unfortunately, this provoked much opposition, and he resigned his post.
Split into simpler sentences: As a pioneer of congregational music in the Merthyr area he was the first choirmaster to substitute women for men in the singing of treble parts. This provoked much opposition, and he resigned his post.