sentences:  Institutional Revolutionary Party
  
  The Institutional Revolutionary Party (, PRI) is a Mexican political party founded in 1929 that held uninterrupted power in the country for 71 years from 1929 to 2000, first as the National Revolutionary Party (, PNR), then as the Party of the Mexican Revolution (, PRM) and finally as the PRI beginning in 1946.The PNR was founded in 1929 by Plutarco Elías Calles, Mexico's paramount leader at the time and self-proclaimed "Jefe Máximo" (Supreme Chief) of the Mexican Revolution.