Complex sentence: As Thirunāvāya was captured, Zamorin proclaimed himself as "the Protector" and took over sole rights of conducting the Māmānkam festival, i.e. the Thirunavaya Wars led to the annexation of Vanneri from Perumpadappu.
Split into simpler sentences: As Thirunāvāya was captured, Zamorin proclaimed himself as "the Protector" and took over sole right of conducting the Māmānkam festival. I.e., the Thirunavaya Wars led to the annexation of Vanneri from Perumpadappu.