 Complete the following phrase:  His career as a virtuoso pianist began in spring 1874 with concerts in Odessa and Kiev. His performances in Rome, Naples, Constantinople, Warsaw, Paris, London and other European cities were a great success. He was interested in the two piano keyboards, a new invention of Edouard Mangeot, which in two months mastered. He developed his repertoire in this new instrument and performed on it with great acclaim in the 