Adozen years after Vasco de Gama's epic voyage round the Cape of Good Hope to India's Malabar coast, the Portuguese in 1510 established a strongpoint at Goa, which thenceforth served as the linchpin of their eastern empire. Alfonso d'Albuquerque, the second Viceroy of Goa, extended the Portuguese presence further east a year later by leading a naval squadron across the Indian Ocean to seize the wellsituated port of Malacca. Discovering that Malacca was a distant vassal of Siam, he immediately dispatched an envoy to Ayutthaya (by Chinese junk) to inform the king of Siam of the Portuguese coup de main. The envoy was well received at the Siamese court and was pleasantly surprised to find that no objections were raised against the Portuguese initiative. Returning to Malacca by the overland route from Ayutthaya to the Andaman coast, he officially apprised the Siamese vassal ports of Tenasserim and Martaban of the new Portuguese presence and friendly intentions. And so, Portuguese relations with the Siamese kingdom started off on the right foot (Bidya 1998, pp. 29–76; Campos 1959; Silva Rego 1982).

A second Portuguese mission visited Ayutthaya in 1512. After a twoyear stay during which the envoy explored trade opportunities for the Portuguese Crown, he returned to Malacca and then Goa accompanied by a Thai embassy. In 1516, Malacca dispatched to Ayutthaya yet another ambassador, who managed to negotiate a treaty of “friendship and commerce” between the kingdoms of Siam and Portugal, the first Siamese compact with a European power. The treaty specified that the Portuguese would be permitted to set up trading posts at Ayutthaya and other Siamese ports, that they would supply Ayutthaya with guns and powder, and that they would be allowed to practise their religion openly and freely. The Portuguese settlement that subsequently emerged at Ayutthaya was headed by a series of captains-major (capitanães-mor), appointed — with the concurrence of the Siamese authorities — by the Estado Português da Índia, instituted in 1505 and headquartered at Goa. In practice, the Estado pursued a hands-off policy. Ayutthaya's Portuguese settlement was left largely to its own devices and, much to the liking of the Siamese authorities, frequently carried out its mercantile activities in defiance of Portuguese royal orders (D’Ávila Lourido 1996, p. 76).