2:40 fourth kingdom. The fourth world kingdom, stronger than any before it, and longer in duration, dominated the world beginning about 129 B.C., becoming a monolithic empire under Augustus in 31 B.C., and continuing until its fall in A.D. 476. However, it divided in A.D. 285 under Emperor Diocletian into eastern and western branches, as indicated by the two legs of the image. The eastern leg, centered at Constantinople, did not fall until A.D. 1453.