Complex sentence: Israel (the northern kingdom) probably began with Omri, who built his capital at Samaria, and it was in Samaria that Yahweh had the title "God of Israel"--no "God of Judah" is mentioned anywhere in the Bible.
Split into simpler sentences: Israel (the northern kingdom) probably began with Omri, who built his capital at Samaria. It was in Samaria that Yahweh had the title "God of Israel"--no "God of Judah" is mentioned anywhere in the Bible.