Career
Mancicidor served in Madrid under Philip II"s secretary of state, Juan de Idiáquez. When Archduke Albert was sent to the Low Countries as Governor General in 1596, he accompanied him as his secretary of state and war. As Secretary of State he was responsible for the confidential correspondence between the Archduke and King Philip III of Spain, his ministers, Spanish ambassadors at their various postings, the governor of Milan, the Viceroy of Naples, and other dignitaries.
As Secretary of War, he countersigned all the Archduke"s military orders.
He was part of the delegation that negotiated the Twelve Years" Truce of 1609–1621. Mancicidor was married twice.
Both were Flemish. Three daughters of the first marriage were christened in Brussels in 1598, 1599, and 1602, and two of the second marriage in 1616 and 1618.
He is known to have had two sons.