Task: Question Generation
Input (English): Passage: Holst was born in Cheltenham, Gloucestershire, the elder of the two children of Adolph von Holst, a professional musician, and his wife, Clara Cox, née Lediard. She was of mostly British descent, daughter of a respected Cirencester solicitor; the Holst side of the family was of mixed Swedish, Latvian and German ancestry, with at least one professional musician in each of the previous three generations.One of Holst's great-grandfathers, Matthias Holst, born in Riga, Latvia, was of German origin; he served as composer and harp-teacher to the Imperial Russian Court in St Petersburg. Matthias's son Gustavus, who moved to England with his parents as a child in 1802, was a composer of salon-style music and a well-known harp teacher. He appropriated the aristocratic prefix "von" and added it to the family name in the hope of gaining enhanced prestige and attracting pupils.Holst's father, Adolph von Holst, became organist and choirmaster at All Saints' Church, Cheltenham; he also taught, and gave piano recitals. His wife, Clara, a former pupil, was a talented singer and pianist. They had two sons; Gustav's younger brother, Emil Gottfried, became known as Ernest Cossart, a successful actor in the West End, New York and Hollywood. Clara died in February 1882, and the family moved to another house in Cheltenham, where Adolph recruited his sister Nina to help raise the boys. Gustav recognised her devotion to the family and dedicated several of his early compositions to her. In 1885 Adolph married Mary Thorley Stone, another of his pupils. They had two sons, Matthias (known as "Max") and Evelyn ("Thorley"). Mary von Holst was absorbed in theosophy and not greatly interested in domestic matters. All four of Adolph's sons were subject to what one biographer calls "benign neglect", and Gustav in particular was "not overburdened with attention or understanding, with a weak sight and a weak chest, both neglected—he was 'miserable and scared'.".
Output (English): What were the full names of Holst's parents?