Excerpts from Books and Wikipedia
"Less than one year after Theodosius had brought the empire together after years of civil war, it was divided once again between Theodosius's inexperienced sons, with Honorius ruling in the west and Arcadius ruling in the east. . . . On August 24, 410 the Roman world was shaken to its core when Alaric the Goth sacked Rome. By the time Honorius died in 423, his empire was plagued by revolts and usurpers." [1001 Days]