[1] In 1618 Sonck was sent by the Dutch East Indies Company as “advocaat-fiscaal” (a district attorney) to Batavia, where he arrived in 1619.
In 1623 he was recalled to Batavia to account for the use of excessive amounts of ammunition at gun salutes (he was to pay for it out of his own pocket).
[2] On 4 May 1624 the governing body in Batavia decided to send him to replace Cornelis Reijersen as commander of the Dutch fort and trading base on Peng-hu, the main island of the Pescadores west of Formosa.
[2] The Pescadores were Chinese territory, and after a failed accord, Nan Juyi, the governor of Fujian, sent an army to attack Peng-hu in July 1624.
[4] On 25 August, after negotiations via Li Dan, head of the illegal traders on Taiwan, Sonck succumbed under the pressure and withdrew his contingent to Formosa, where he founded Fort Zeelandia near the town Anping.