In early Philippine history, the Tagalog Bayan of Maynila was a major Tagalog city-state on the southern part of the Pasig River delta, where the district of Intramuros currently stands.

Historical accounts indicate that the city-state was led by sovereign rulers who were referred to with the title of raja ("king"). Other accounts also refer to it as the "Kingdom of Luzon", although some historians suggest that this might rather refer to the Manila Bay region as a whole.

The earliest oral traditions suggest that Maynila was founded as a Muslim principality in as early as the 1250s, supposedly supplanting an even older pre-Islamic settlement. However, the earliest archeological findings for organized human settlements in the area dates to around 1500s. By the 16th century, it was already an important trading center, with extensive political ties with the Sultanate of Brunei and extensive trade relations with traders from the Ming dynasty. With Tondo, the polity on the northern part of the Pasig River delta, it established a duopoly on the intraarchipelagic trade of Chinese goods. Maynila and Luzon are sometimes associated with the Bruneian legends which describe a settlement called "Seludong", but Southeast Asian scholars believe this refers to a settlement Mount Selurong in Indonesia. For political reasons, the historical rulers of Maynila maintained close cognatic ties through intermarriage with the ruling houses of the Sultanate of Brunei, but Brunei's political influence over Maynila is not considered to have extended to military or political rule. Intermarriage was a common strategy for large thassalocratic states such as Brunei to extend their influence, and for local rulers such as those of Maynila to help strengthen their family claims to nobility. Actual political and military rule over the large distances characteristic of Maritime Southeast Asia was not possible until relatively modern times.