Complex sentence: The principal line of the Toki lost their possessions in 1542 during the civil wars that decimated Mino Province, when Toki Yoshiyori (then governor of Mino) was defeated by Saitō Dōsan.
Split into simpler sentences: The principal line of the Toki lost their possessions in 1542 during the civil wars that decimated Mino Province. Toki Yorinari (then governor of Mino) was defeated by Saitō Dōsan.