In the early 19th century, Penang became a centre of spice production and trade within Southeast Asia. The cultivation of pepper began soon after the founding of George Town in 1786. The production of spices, including nutmeg and clove, gradually grew more varied and the booming spice trade led to the opening of spice farms all over Penang. The export of spices through the Port of Penang also enabled the British East India Company to cover the administrative costs of Penang. Furthermore, the agricultural plantations would fuel the growth of several villages, such as Air Itam and Balik Pulau on the island, and Bukit Mertajam in Province Wellesley. Malay refugees fleeing the Siamese invasion of Kedah and Chinese immigrants formed the bulk of workers in these agricultural estates. Other areas, such as Bayan Lepas on the island and Kepala Batas in Province Wellesley, were founded as rice-producing estates.