WILLEKENS, Jacobus, Dutch admiral, born in Breda in 1571; died in Ternate in 1633. He was in the employ of the East, and West Indian company for years, mid in 1620 presented to John Usseling, president of the board of directors, a memoir in which he advocated a combined attack on the Spanish possessions of the Atlantic and Pacific coast. Usseling commended the memoir to the directors, and in 1623 the expedition was decided upon. Willekens, being appointed commander-in-chief, directed the armament of two fleets. One, in command of Jacob L'Hermite-Clerk, sailed from Amsterdam, 29 April, 1623, to operate against Peru and Mexico, while the main fleet, under Willekens, was to attack Brazil, and sailed from Texel, 22 December, 1623. Early in June, 1624, he began operations against San Salvador da Bahia, and after his vice-admiral. Piet Hein (q. v.), had crossed the bar on 10 June and captured the Portuguese fleet, the city surrendered at discretion on the following day. Bishop Texeira preached the war against the heretics among the Indians, and the Portuguese, having rallied, besieged Willekens: but the latter repelled them, and led an expedition into the interior, on his return from which he was defeated by the Indians. Surrendering the command to Hein, he sailed, 24 August, 1624, for Amsterdam to obtain re-enforcements. He returned in June, 1625, but found Bahia abandoned by Hein and in the possession of a Spanish-Portuguese fleet, which he attacked. Being driven back, he sailed to the south, landing at intervals and destroying the Portuguese establishments. Chased by the Spanish fleet, he returned to Holland, where he learned of the new expedition that had been sent to Brazil under command of Hein in 1626 and sailed to his succor, he made a successful attack against Rio de Janeiro, which paid ransom, and joined Hein ; but the two admirals disagreeing as to the chief command, they separated and Willekens returned to Amsterdam. he afterward commanded in the East Indies, dying at Ternate after a successful attack against Manila. Willekens's clerk wrote an account of the expedition to Brazil, and it was published in Dutch (Amsterdam, 1626), but is best known in the French version, entitled " Journal de l'expedition entreprise par ordre de nos seigneurs des Etats-Generaux, au Bresil, et du sidge et de la capture de Bahia, sous les ordres de l'Amiral Jacob Willekens " (1629).