OMAHA, Neb. (AP) — Creighton University President Timothy Lannon has announced that he’ll be leaving his post sooner than expected.

Lannon cited his health in an email to Creighton staffers and students on Tuesday and said he’d be resigning effective Jan. 20, six months earlier than planned. He’d begun planning his retirement after falling ill a year ago during Thanksgiving Mass.

Lannon returned to Creighton in 2011 as Creighton’s 24th president. Chris Bradberry, who is dean of the School of Pharmacy and Health Professions, will become interim president on Dec. 21.