He first studied theology at Giessen, but after the campaign of 1814, in which, like his brother August, he took part as a Hessian volunteer, began the study of jurisprudence, and in 1818 established himself as Privatdocent of civil law at Giessen.
Equity here is defined to mean "any body of rules existing by the side of the original civil law, founded on distinct principles, and claiming incidentally to supersede the civil law in virtue of a superior sanctity inherent in those principles."
Vansittart's brother, Robert Vansittart (1728-1789), who was educated at Winchester and at Trinity College, Oxford, was regius professor of civil law at Oxford from 1757 until his death on the 31st of January 1789.
The members accidentally discovered that the fear of it had a great influence over the lawless but superstitious blacks, and soon the club expanded into a great federation of regulators, absorbing numerous local bodies that had been formed in the absence of civil law and partaking of the nature of the old English neighbourhood police and the ante-bellum slave patrol.
In January 1543/4 he was appointed first regius professor of civil law.