June and Jennifer Gibbons were so close that they created an exclusive language that was unintelligible to outsiders except for their little sister. At age 16 they were committed to a mental hospital.. While there they became convinced one twin had to die so the other could live a normal life. Jennifer told Margaret Wallace, "I'm going to die. We've decided." Within hours of their release Jennifer died of sudden inflammation of the heart. After losing her twin, June resumed a normal life.