Complex sentence: He moved to University College London in September 1997, where he was Senior Lecturer before he was appointed Professor of Classics and in 2006 he was appointed to the Chair of Ancient History, which was subsequently redesignated the Grote Professorship.
Split into simpler sentences: He moved to University College London in September 1997, where he was Senior Lecturer before being appointed Professor of Classics. In 2006 he became Chair of Ancient History, which was subsequently redesignated the Grote Professorship.