Complex sentence: His early life was in Dublin, Ireland, where he started a stamp exchange scheme with school classmates at eight years of age that by 1958 had become "The Shamrock Stamp Club" a mail order sales business promoted by advertising in Mickey Mouse comics.
Split into simpler sentences: His early life was in Dublin, Ireland, where he started a stamp exchange scheme with school classmates at eight years of age. By 1958 this had become "The Shamrock Stamp Club" a mail order sales business promoted by advertising in Mickey Mouse comics.