In 1571, Ōmura Sumitada opened it as a gateway for Portuguese trade and created six districts. In 1580, Nagasaki and Mogi were donated to the Society of Jesus; in 1587, Toyotomi Hideyoshi took direct control and established it as an overseas trading port.
Some Nagasaki City sources indicate port surveying and town construction began in 1570, but 1571 is used—marking Portuguese ship arrival and full opening.
Certainty: MediumHow far the account above is supported by the cited sources. It does not refer to the precision of the coordinates or the dating.