Given the following context:

Anton Rubinstein was a famous Russian pianist who had lived, performed and composed in Western and Central Europe before he returned to Russia in 1858. He saw Russia as a musical desert compared to Paris, Berlin and Leipzig, whose music conservatories he had visited. Musical life flourished in those places; composers were held in high regard, and musicians were wholeheartedly devoted to their art. With a similar ideal in mind for Russia, he had conceived an idea for a conservatory in Russia years before his 1858 return, and had finally aroused the interest of influential people to help him realize the idea.
Rubinstein's first step was to found the Russian Musical Society (RMS) in 1859. Its objectives were to educate people in music, cultivate their musical tastes and develop their talents in that area of their lives. The first priority of the RMS acted was to expose to the public the music of native composers. In addition to a considerable amount of Western European music, works by Mussorgsky and Cui were premiered by the RMS under Rubinstein's baton. A few weeks after the Society's premiere concert, Rubinstein started organizing music classes, which were open to everyone. Interest in these classes grew until Rubinstein founded the Saint Petersburg Conservatory in 1862.According to musicologist Francis Maes, Rubinstein could not be accused of any lack of artistic integrity. He fought for change and progress in musical life in Russia. Only his musical tastes were conservative—from Haydn, Mozart and Beethoven to the early Romantics up to Chopin. Liszt and Wagner were not included. Neither did he welcome many ideas then new about music, including the role of nationalism in classical music. For Rubinstein, national music existed only in folk song and folk dance. There was no place for national music in larger works, especially not in opera. Rubinstein's public reaction to the attacks was simply not to react. His classes and concerts were well attended, so he felt no reply was actually necessary. He even forbade...

answer the following question:

What is the last name of the person who forbade his students to take sides? 

Rubinstein