IOWA CITY — Here is a timeline of key events in Bruce Harreld’s five-year tenure as president of the University of Iowa:Read the story: Bruce Harreld retiring from the UI 2015Jan. 15: Former UI President Sally Mason announces plans to retire Aug. 1, telling The Gazette, “There have been plenty of challenges.”March 25: Regents identify UI Vice President for Medical Affairs Jean Robillard as their choice for interim UI president.