Complex sentence: Saint Alban was long regarded as a genuine martyr saint, the protomartyr of Britain, and for much of the 20th century controversy centred on the date of his martyrdom (see further'Dating Controversy', above).
Split into simpler sentences: Saint Alban was long regarded as a genuine martyr saint, the protomartyr of Britain. For much of the 20th century controversy centred around the date of his martyrdom (see further'Dating Controversy', above).