Complex sentence: Houghton Mifflin Harcourt Learning Technology originally started as Riverdeep Interactive Learning, a publishing house for educational online and CD-ROM products based in San Francisco and Dublin, Ireland, founded in 1995, Riverdeep was principally the creation of the Irish ex-investment banker Barry O'Callaghan.
Split into simpler sentences: Houghton Mifflin Harcourt Learning Technology originally started as Riverdeep Interactive Learning, is a publishing house for educational online and CD-ROM products based in San Francisco and Dublin, Ireland. Founded in 1995, Riverdeep was principally the creation of the Irish ex-investment banker Barry O'Callaghan.