de Wichfeld, Monica Emily (1894–1945), Danish resistance heroine, was born 12 July 1894 in London, only daughter and eldest of four children of John George Massy-Beresford (1856–1923), landowner, and Alice Elizabeth Massy-Beresford (née Mulholland; 1869–1948), daughter of the 1st Baron Dunleath. Monica's paternal grandfather was the Rev. John Massy, a native of Co. Limerick who became dean of Kilmore; he married (1851) a Scottish heiress, Emily Sarah Beresford, and added ‘Beresford’ to his surname by royal licence (1871). The family's home was St Hubert's, near Crom Castle, Co. Fermanagh. Monica spent her childhood there, and was educated at home and then in France and Germany. Still in her teens, she participated in the Larne gun-running (April 1914): her father was a leader of the Ulster Volunteers in Co. Fermanagh, and she accompanied him when he travelled by car to Larne to pick up a load of the guns and ammunition.
After the outbreak of World War I, Monica moved to London to work in a soldiers' canteen; two of her brothers were in the army, and one – John Clarina (b. 1897) – was killed in action in France in August 1918. In London she met and married (1916) Jørgen de Wichfeld (1885–1966), a Danish aristocrat attached to his country's legation. He had inherited a vast estate, Engestofte, near Maribo, in Lolland. The couple, with their infant son (b. 1919), settled there in the early 1920s. Monica became a Danish citizen. A daughter and another son were born in 1922 and 1923 respectively.
The Engestofte estate was in deep financial difficulty. Jørgen proved incapable of running it, so Monica increasingly assumed that role – albeit with limited success. Meanwhile, she fell in love with Curt, Greve (Count) Haugwitz-Hardenberg-Reventlow (1895–1969), younger brother of a neighbouring landlord; of German stock, he had been a German army officer during the first world war. Their liaison, tolerated by Jørgen, lasted nine years. Reventlow was later married – briefly – to Barbara Hutton, the Woolworth heiress. The Wichfelds' finances were further undermined by the 1929 stock market crash, and in 1930 the Engestofte house was let in order to raise money. Monica, Jørgen, and the children were taken in by Monica's mother who, after her husband's death, had retired to Rapallo on the Italian Riviera. Monica then embarked on an international business career, in costume jewellery and cosmetics; her modest success sustained the family's fortunes until the start of the second world war. Despite her straitened circumstances, she lived in considerable style throughout the 1920s and 1930s – wintering in Italy or the south of France, frequenting fashionable hotels, dressing in couturier clothes, and enjoying the society of wealthy American expatriates and European nobility. She was a handsome woman, though not conventionally pretty.
The Wichfelds stayed on in Italy until September 1941. Ordered to leave because of their outspoken anti-Fascism, they returned to Denmark – now under German occupation. Back in Engestofte, Monica resolved to work against the Nazis. She began by assisting in the distribution of underground publications, but was soon giving shelter to fugitives and allowing her lands to be used for parachute drops of supplies to the resistance. Eventually, she was put in charge of the resistance network in Lolland, reporting direct to Flemming Muus, an agent of the British Special Operations Executive who was leader of the Danish resistance; he subsequently married Monica's daughter (she too was in the resistance). The arrest of three key resistance personnel at Århus in December 1943 had catastrophic consequences: under torture, they gave away the names of many associates, including Monica. She was arrested by the Gestapo 13 January 1944. In May 1944 she was tried by court-martial and, with three others, condemned to death. Her sentence caused outrage in Denmark and after a few days it was commuted to life imprisonment. Monica was transported to a prison at Cottbus, in eastern Germany. In January 1945, with the Russian army approaching Cottbus, she was taken in a crowded cattle train to Waldheim prison camp. She developed viral pneumonia and died there 27 February 1945.
She is commemorated in Mindelunden, the park in Copenhagen honouring the dead of the Danish resistance, and her name is on the war memorial in the Church of Ireland church in Derrylin, Co. Fermanagh.