Culper Ring The Culper Ring was a spy ring organized by Major Benjamin Tallmadge under the orders of General George Washington in the summer of 1778 during British occupation of New York City at the height of the American Revolutionary War . Their name was derived from the aliases taken by two of its main members , Abraham Woodhull and Robert Townsend , who were known as " Samuel Culper , Sr . " and " Samuel Culper , Jr . " respectively . Purpose . The Ring ' s task was to send messages to General George Washington about the activities of the British in New York . They operated mostly in New York , Long Island and Connecticut . The Ring conducted covert operations until after the end of the American Revolutionary War , but its heyday was between 1778 and 1781 . Establishment . After the battle of Monmouth in late June 1778 , British forces under General Sir Henry Clinton retreated to Sandy Hook , New Jersey . From there , they took a ship for New York City , which they had already occupied for almost two years ( since General Washington ' s defeat at the Battle of Fort Washington in September 1776 ) . General Washington was well aware of the need for good intelligence , and he asked one of his officers , Major Benjamin Tallmadge , to recruit people who could be trusted to collect it in New York City . Secrecy . Secrecy was so strict that Washington did not know the identity of all the operatives . The general public was not aware of the Ring ' s existence until the 1930s . " Culper Junior ’ s " identity was discovered in 1939 , with the discovery of a trunk of old letters in the Townsend family home . Historian Morton Pennypacker noticed the resemblance of the handwriting in these letters and letters written by Robert Townsend in George Washington ' s collection . Among the techniques they used to relay messages were coded messages published in newspapers and developing a method of using invisible ink , called a sympathetic stain , to write between the lines of what appeared to be a typical letter . Women were also an integral part of the Culper Ring . At that time , women were expected to share their husbands ' beliefs and not be directly and openly involved in politics , which meant that they were less likely to be suspected of being spies . Known activities . Once Townsend ’ s reports reached Setauket , Caleb Brewster and his men ferried them across Long Island Sound , where Tallmadge ’ s dragoons were waiting to carry it to Washington ’ s headquarters . Brewster had been in New York City years earlier when the British caught Nathan Hale with drawings of their fortifications and hanged him . Perhaps with Hale in mind , Washington made sure the Culper Ring spies had more support . Through Tallmadge , he provided them with code s , dead drop s , and aliases . Members were given code names . For example , George Washington ' s code was 711 . Anna Strong was a resident of Long Island , New York . She helped pass along messages from the spy ring by posting pre - arranged signals to indicate when one of the spies was ready to submit intelligence . If Strong hung a black petticoat on her clothesline , it meant Brewster had arrived in town in his whaleboat . Next to that she would hang a quantity of white handkerchiefs . The specific number of handkerchiefs indicated one of six hiding places where Brewster might be located . Abraham Woodhull , another local resident , used Strong ' s signals to go meet Brewster at one of the meeting - places . Woodhull was known in dispatches as " Samuel Culper , Sr . " , and Townsend was referred to as " Samuel Culper , Jr . " Townsend ' s role was finally determined in 1939 by handwriting analysis , and has since been confirmed by other evidence . Benedict Arnold . Tallmadge was Washington ' s trusted contact / courier at his headquarters to the Connecticut contacts of the Culper ring and other spies . When Major John André was captured , his papers showing Benedict Arnold ' s treason were brought to Tallmadge ' s Dragoons . He knew to immediately forward them to Washington , but Tallmadge ' s commander had already sent a note telling of the capture of André to Arnold . Arnold immediately escaped to the British ship down the Hudson , before anyone else knew what was happening . Agent 355 . One of those who allegedly aided the Culper Ring was an operative known only as “ 355 , ” the group ’ s code for “ lady . ” Some historians believe she was the only member of the ring arrested by the British and hanged as a spy . Others claim that she was a prisoner aboard the British hulk , " The Jersey " , and gave birth to Robert Townsend ' s illegitimate child , though that part of the story has been discredited . Robert Townsend did allegedly father a child by another woman after 355 ' s death . Tallmadge . Nathan Hale and Tallmadge were close friends at Yale , and Tallmadge ' s entry into the secret world was not accidental , nor did it begin with the Culper Ring in 1778 . As early as 1777 , Tallmadge acted as the operative John Clark ' s contact in Connecticut when Clark was based on Long Island . Before that , he worked for the spymaster Nathaniel Sackett , who was later fired .