sentences:  The Nawab could also be unpredictable and devious, and his breach of promise in failing to surrender Tiruchirappalli to Hyder Ali in 1751 was at the root of many confrontations between Hyder Ali and the British.When Hyder Ali swept into the Carnatic towards Arcot on 23 July 1780, with an army estimated at 86–100,000 men, it was not the Nawab, however, but the British who had provoked Hyder Ali's wrath, by seizing the French port of Mahé which was under his protection.Much of the ensuing war was fought on the Nawab's territory.