Answer
King Michael I of Romania reigned twice as king. The first time was from 20 July 1927 until 8 June 1930, and the second time was from 6 September 1940 until 23 August 1944. During his first reign, Michael was a minor and his uncle, Prince Carol, acted as regent. During his second reign, Michael played an important role in the overthrow of the pro-Nazi regime of Ion Antonescu.