Originally minted for use in Ireland, St. Patrick coppers had a long and varied history. An English Quaker merchant in Dublin named Mark Newby (or Newbie) acquired a large supply of these coins which he took with him in 1681 when he emigrated to West New Jersey (New Jersey was divided into separate Eastern and Western colonies from 1676-1702). On May 18, 1682 the General Free Assembly of West New Jersey granted Newby's coppers legal tender status and allowed them to circulate as small change at the rate of a halfpenny, replacing wampum.
The only restrictions were that Newby had to put up surety (300 acres of land) that he would exchange the coppers for "pay equivalent" on demand and that one was not required to accept more than five shillings in coppers at one time. When Newby died about a year later, in the fall of 1682, his estate included £30 in coppers, estimated at roughly 10,800 coins. Newby's St. Patrick coppers filled an important need in local commerce and remained in circulation throughout the colonial period. In fact, in 1881 the eminent New Jersey copper specialist Edward Maris stated that St. Patrick coppers continued to be found in change in western New Jersey into the early 19th century.
Several theories have been put forth on the origins of the Saint Patrick coppers. The most plausible is that the tokens were minted in Dublin around the period 1674-1675. A single smaller size or "farthing" coin was found in a hoard of 273 coins recovered from the yacht Mary which sank on March 24, 1675, on its way from Dublin to Chester. From this it is certain the production of these coins date to at least 1675. Although there is no evidence as to how much earlier the coins were minted, it is suspected they were part of a coinage sanctioned by Arthur, Earl of Essex, who was the Lord Lieutenant of Ireland from 1672 to 1677.