The East India Company took over the territories of Penang Island, which it called Prince of Wales Island, and then Province Wellesley on the mainland, from the Kedah Sultanate in the latter part of the 18th century. In return the Sultanate received payment, and some form of assurances of defensive help against the expansionist ambitions of the Siamese kingdom. The military and diplomatic situation in the area turned subsequently on the precise nature and effectiveness of the East India Company's commitment to defensive arrangements for Kedah against the Siamese.