Excerpt Josephus traces their origins to the foreigners (he calls them Cutheans) forcibly brought into the territory of Israel after its defeat by the Assyrians in 722 b.c.e. (2 Kgs. 17). The earliest evidence of the schism between Jew and Samaritan comes from the Persian period. This includes the more ambiguous mention of Samaritans in Ezra 4, which could be a geographical designation of peoples rather than a reference to a religious group.
Anderson, Robert T. “Samaritans.” Ed. David Noel Freedman, Allen C. Myers, & Astrid B. Beck. Eerdmans dictionary of the Bible 2000 : 1159. Print.