In 1603 Raja Bongsu was instrumental in forging the early diplomatic relations with the Dutch by lending assistance to Admiral Jacob van Heemskerk on 25 February 1603 in attacking and plundering the Portuguese carrack, the Santa Catarina, in the Johor River estuary off present-day Singapore.[2] He was also responsible for sending one of the first diplomatic missions of a Malay ruler to the Dutch Republic in the same year. Headed by Megat Mansur, the Johor embassy sailed to Europe on the ships of Admiral van Heemskerk in 1603. Megat Mansur did not survive the voyage, but other members of the Johor embassy did and returned with the fleet under the command of Admiral Cornelis Matelief de Jonge in 1606.[3] In that year, Raja Bongsu formally ratified two treaties with the Dutch (dated 17 May and 23 September 1606) and signed himself as the co-ruler of Johor.[4] He also lent active assistance to Admiral Matelief during his seaborne attack on Portuguese Melaka in or around May 1606.