Claimed / alleged second Graeff line:
The official statement of the family association reads: An origin of the originally German or Dutch family Op den Graeff from the Von Graben house cannot be verified. But this theory is maintained by their descendants.
It is said that they originally descendant from Wolfgang von Graben) 1465-1521) who arrived to Holland in 1483. His younger son Abraham op den Graeff (1485/1490-1561 died in Düsseldorf), who possible married to [Matriarch] van de Aldekerk (1500-1525), was the claimed ancrestor of the Op den Graeff line in Kleve (Germany), while his elder brother Pieter Graeff (born 1484) was the ancrestor of the dutch (De) Graeff family.
During the Thirty Years War, many genealogical records housed in churches were destroyed.
The op den Graeffs where Mennonits and an immigrate to Krefeld. In 1683 some of the Op den Graeffs descendents migrated to the United States. Abraham op den Graeff, one of the three sons of Isaac Hermansz op den Graeff was invited by his cousin William Penn in 1681 to leave Krefeld for Philadelphia. They are among the thirteen families ("Original 13") often referred to as the Germantown, Philadelphia, Pennsylvania founders, who arrived on the ship Concord on October 6, 1683. Surnames were changed to Updengraff at some point either upon their arrival to Philadelphia or shortly thereafter. Another american Op den Graeff family, Updegrove, descendat from one John William op den Graeff (1732-1800/1804). They arrived to Germantwn around 1754.
* Hermann op den Graeff (1585-1642), called the Mennonite Lord-Bischop of Crefeld, Alleged son of Anna op den Graeff van de Aldekerk
* Abraham Isacks op den Graeff (1649-1731), one of the Original 13, the first german settlers in America, signer of the first organized religious protest
against slavery in colonial America