Complex sentence: Irwin was appointed as the C.E.O. of Dublin International Sports Council (DISC) in 1993 under the Chairmanship of Dr. Tony O'Reilly who built the organisation from scratch.
Split into simpler sentences: Irwin was appointed as the C.E.O. of Dublin International Sports Council in 1993. Under the Chairmanship of Dr. Tony O'Reilly who built the organisation from scratch.