Under its previous name of Siam, the Kingdom of Thailand was a frequented intersection of the east-west trade route with much of its culture, religion and food influenced by the Arabs and Persians bringing rich spices to the region. Western influences started in the 1500s and until then, Indian neighbours taught them how to use chillies to make rich, spicy curries. During the Columbian Exchange, travellers from Portugal and Spain brought raw produce from Europe and the Americas, including tomatoes, chillies, corn, papaya, pea eggplants, pineapple, pumpkins, cashews, coriander and peanuts. As with many Southeast Asian countries, there are correlating flavours and recipes found between regions – Isan from the northeast is influenced by Laos and Khmer cultures, while southern Thai food is much closer to Malay and Indian cuisine. Central Thai food is the cuisine of the flat and wet central rice-growing plains, the site of the former Thai kingdoms of Sukhothai and Ayutthaya, and the Dvaravati culture of the Mon people from what we now know as Myanmar or Burma.