Complex sentence: The raid on Cranganore and the defection of Tanur to the Portuguese were serious setbacks to the zamorin, pushing the front-line of battles north and effectively placing the Vembanad lagoon out of reach.
Split into simpler sentences: The raid on Cranganore and the defection of Tanur to the Portuguese were serious setbacks for the zamorin. These events pushed the front-line of battles north and effectively placed the Vembanad lagoon out of reach.