Complex sentence: William M. Fullarton (born 1882) was a Scottish association football player active prior to the First World War who played primarily as a centre-half and made over fifty appearances in The Football League.
Split into simpler sentences: William M. Fullarton (born 1882) was a Scottish association football player active prior to the First World War. He played primarily as a centre-half and made over fifty appearances in The Football League.