Arnoldus van Hardenbergh was born in Holland and, as a free merchant, he sailed to New Netherland in 1644. Van Hardenbergh took an active part in public affairs, and, in 1645, was one of the three merchants who were members of the first assembly of the Nine Men.
In March 1649, Cornelis Melyn, who had appealed a decision of the New Netherland Court to the Dutch parliament in the Hague, arrived back in New Amsterdam. Melyn was protected by a letter of safe conduct issued to him by the Dutch parliament. A public meeting was convened at which Melyn produced the order of the Dutch parliament mandating that Director-General Stuyvesant attend the hearing of Melyn's appeal in the Hague. When Melyn handed the mandamus to Arnoldus van Hardenbergh to be read aloud to those assembled, Stuyvesant snatched the document from Van Hardenbergh's hands, tearing the official seal from the document in the process. Van Hardenbergh, who had been a victim of judicial oppression under both the Kieft and Stuyvesant administrations, was a signatory to the Great Remonstrance of New Netherland (July 28, 1649).
As a merchant, Van Hardenbergh was required to travel abroad and to ensure that his business affairs were managed properly in his absence, he executed a Power of Attorney (Available at the New York State Archives in favor of Jan Lourensen Appel and Adriaen Jansen. In the Register of the Provincial Secretary of New Netherland there is an entry dated October 20, 1649, in which Jan Louresen Appel, as attorney of Arnoldus van Hardenbergh, seeks to collect "from Mr. Andries Hudden, commissary in the service of the honorable West India Company, residing at Fort Nassau on the South River aforesaid, the sum of two hundred and twenty-eight guilder, six stiver; from Symon Root, trader there on the South River above mentioned, the sum of three hundred and twenty-eight guilder, and from David Davitsz the sum of two hundred-eight guilder, and likewise from one Tomas Broen, also residing there, the sum of eighty-four guilder and two stiver, all payable in beavers, as appears by the annexed account and authentic bonds."
Some time later, and before 1659, Arnoldus Van Hardenbergh appears to have left New Netherland and returned to Holland.
Charles Elliott Fitch. Encyclopedia of Biography of New York, Vol 5 at 133.