Clissmann, Helmut E. (1911–97), German intelligence officer, was born at Aachen in northern Germany. His association with Ireland dates from 1930, when he made his first visit to Dublin as a member of the left-wing nationalist Young Prussian League. Through its link with romantic German nationalism and socialism the league had become interested in the IRA. Clissmann returned in 1933 as an exchange student at TCD, and later worked on a doctoral thesis, ‘The wild geese in Germany’, at Frankfurt University. During these visits to Ireland he became interested in the activities of the IRA, and in time got to know many leading republicans, including Seán MacBride (qv), Frank Ryan (qv), and Sean Russell (qv). He married Elizabeth (Budge) Mulcahy, a member of a prominent Sligo republican family, with whom he had four sons and three daughters. He managed to return to Ireland in 1936, when he was appointed director of the Dublin branch of the German Academic Exchange; he later established and ran branches of the organisation in Cork and Galway. As director of the exchange he helped to arrange a visit to Germany for his friend Francis Stuart (qv) in 1939.
Clissmann's early radical politics made him appear unreliable in the eyes of the national socialists in Germany, and when, in the summer of 1938, he attempted to pass on information concerning recent developments within Irish republicanism he was rebuffed by the Abwehr (German military intelligence) on the grounds that it was forbidden to become involved in the Irish question. However, as attitudes altered, the German minister in Ireland, Dr Eduard Hempel (qv), used him to establish contacts with the IRA. On the outbreak of war in 1939 he was ordered to return to Germany. He initially ran the German Academic Exchange in Copenhagen, but later joined the Brandenburg regiment of the German army, before working for the Abwehr as an adviser on Irish affairs.
Clissmann tried to return to Ireland during the war by means of the unsuccessful Operation Lobster (August 1940), which was an attempt to land him and a radio operator at Sligo, from where it was hoped they could, with IRA help, make their way to England. He interested his army superiors in the case of Frank Ryan, who was being held in a Spanish prison after fighting in the civil war for the International Brigade, and helped to secure his release. Both he and his wife assisted Ryan during his subsequent years in Germany. The two men were involved in Operation Osprey, in which they planned to land in Co. Roscommon with funds for the IRA, but this was never put into action. He continued to examine ways in which Ireland might be of use to the Germans, and through discussions with Leopold Kerney (qv), Irish minister in Madrid, attempted to monitor changes in Ireland's foreign policy.
Clissmann subsequently joined the Afrika corps and fought in north Africa; he escaped Tunis shortly before its fall. In 1945 he found himself a prisoner of war; he spent a year in an interrogation prison at Bad Nenndorf, near Hanover, where he was questioned intensively by the British about his involvement with Ireland. His wife had returned to Ireland and in 1948 she secured him an Irish visa. He lectured in German at TCD, and again worked for the German Exchange Service; he was also engaged by the Goethe Institute. He then turned to business and established an agency which imported pharmaceutical products; he became a founder member of what was later known as the Irish Pharmaceutical Healthcare Association. With Dr Alfred Kolb he was instrumental in establishing St Killian's German school in Dublin, of which he was made honorary life president. He was also a founder member of the Irish section of Amnesty International, and appears to have maintained contacts with the IRA after the war. He died 6 November 1997 in Dublin.