Task: Question Answering
Input (English): Passage: Balakirev's despotism strained the relationship between him and Tchaikovsky but both men still appreciated each other's abilities. Despite their friction, Balakirev proved the only man to persuade Tchaikovsky to rewrite a work several times, as he would with Romeo and Juliet. At Balakirev's suggestion, Tchaikovsky based the work on Balakirev's King Lear, a tragic overture in sonata form after the example of Beethoven's concert overtures. It was Tchaikovsky's idea to reduce the plot to one central conflict and represent it musically with the binary structure of sonata form. However, the execution of that plot in the music we know today came only after two radical revisions. Balakirev discarded many of the early drafts Tchaikovsky sent him and, with the flurry of suggestions between the two men, the piece was constantly in the mail between Moscow and Saint Petersburg.Tchaikovsky allowed the first version to be premiered by Nikolai Rubinstein on March 16, 1870, after the composer had incorporated only some of Balakirev's suggestions. The premiere was a disaster. Stung by this rejection, Tchaikovsky took Balakirev's strictures to heart. He forced himself to reach beyond his musical training and rewrote much of the music into the form we know it today. Romeo would bring Tchaikovsky his first national and international acclaim and become a work the kuchka lauded unconditionally. On hearing the love theme from Romeo, Stasov told the group, "There were five of you; now there are six". Such was the enthusiasm of the Five for Romeo that at their gatherings Balakirev was always asked to play it through at the piano. He did this so many times that he learned to perform it from memory.Some critics, among them Tchaikovsky biographers Lawrence and Elisabeth Hanson, have wondered what would have happened if Tchaikovsky had joined Balakirev in 1862 instead of attending the Conservatory. They suggest that he might have developed much more quickly as an independent composer, and offer as proof the fact that Tchaikovsky did not write his first wholly distinct work until Balakirev goaded and inspired him to write Romeo. How well Tchaikovsky might have developed in the long run is another matter. He owed much of his musical ability, including his skill at orchestration, to the thorough grounding in counterpoint, harmony and musical theory he received at the Conservatory. Without that grounding, Tchaikovsky might not have been able to write what would become his greatest works. 
Question: What was the first names of Tchaikovsky's two biographers?
Output (English): Elisabeth.