Cornelis de Graeff, also Cornelis de Graeff van (Zuid-)Polsbroek (October 15, 1599 – May 4, 1664) is the most illustrious member of the De Graeff family.
He is a mayor of Amsterdam from the Dutch Golden Age and a powerful Amsterdam regent after the sudden death of stadholder William II of Orange.
Like his father Jacob Dircksz de Graeff he opposes the house of Orange, and is the moderate successor to the republican Andries Bicker.
In the mid 17th century he controls the city's finances and politics, and in close cooperation with his brother Andries de Graeff and their nephew Johan de Witt the Netherlands political system.
Cornelis de Graeff follows in his father’s footsteps and, between 1643 and 1664, is appointed mayor some ten times.
De Graeff is a member of a family of regents who belong to the republican political movement also referred to as the ‘state oriented’, as opposed to the Royalists.
Cornelis de Graeff is also the founder of a regent dynasty that retains power and influence for centuries and produces a number of ministers.
He is Lord of the semi-sovereign fief (allodiale hoge heerlijkheid) Zuidpolsbroek and an Ambachtsheer (Lord of the Manor) of Sloten, Sloterdijk, Nieuwer-Amstel, Osdorp and Amstelveen, near Amsterdam, and castlelord of Ilpenstein.
De Graeff is also President of the Dutch East Indies Company, and a chief councilor of the Admiralty of Amsterdam.
His brother Andries De Graeff is an illustrious art patron and collector.
During his life De Graeff is often called "Polsbroek" or "Lord Polsbroek".
