Complex sentence: Gregory John Barrington "Greg" Mills (born 9 May 1962) heads the Brenthurst Foundation, based in Johannesburg, South Africa, established in 2005 by the Oppenheimers to strengthen African economic performance.
Split into simpler sentences: Gregory John Barrington "Greg" Mills (born 9 May 1962) heads the Brenthurst Foundation, based in Johannesburg, South Africa. The Foundation was established in 2005 by the Oppenheimer family to strengthen African economic performance.