Original: Through time, these crowns have been interpreted variously as representative of the conquered kingdoms of Kazan, Astrakhan, and Siberia, or as representing the unity of "All the Russias" (Great Russia, the present-day Russian Federation; Little Russia, now the Ukraine; and White Russia, now Belarus).
Simplified: They have been seen as the conquered kingdoms of Kazan, Astrakhan and Siberia, or as the coming together of 'All the Russias' - Grand Russia (Russia), Little Russia (today's Ukraine) and White Russia (Belarus).