In February 1865 Brahmss mother died, and he began to compose his large choral work A German Requiem Op. 45, of which six movements were completed by 1866. Premieres of the first three movements were given in Vienna, but the complete work was first given in Bremen in 1868 to great acclaim. A seventh movement (the soprano solo "Ihr habt nun Traurigkeit") was added for the equally successful Leipzig premiere (February 1869), and the work went on to receive concert and critical acclaim throughout Germany and also in England, Switzerland and Russia, marking effectively Brahmss arrival on the world stage. Brahms also experienced at this period popular success with works such as his first set of Hungarian Dances (1869), the Liebeslieder Walzer, Op. 52 (Brahms), (1868/69), and his collections of lieder (Opp. 43 and 46–49). Following such successes he finally completed a number of works that he had wrestled with over many years such as the cantata Rinaldo (cantata) (1863–1868), his Two String Quartets, Op. 51 (Brahms) Op. 51 nos. 1 and 2 (1865–1873), the third piano quartet (1855–1875), and most notably his Symphony No. 1 (Brahms) which appeared in 1876, but which had been begun as early as 1855.
Question: How many years did it take Brahm to complete the third piano quartet?
Answer: 20