the kingdom of romania (or 'romania' after 1969) was a constitutional monarchy which existed between 13 march 1881 and 30 december 1947, specified by the first (in 1866), and respectively, the second constitution of roumania. thus, the kingdom of romania began with the reign of king carol i of romania and later replaced by michael i of romania . it's prime minister was ion antonescu who was prime minister from 1940-1944 . he was later executed in 1946 2 year's after the defeat of nazi germany,italy,hungary,croatia,romania,bulgaria and japan the countries in the axis powers who were defeated in 1945 .