Other important plays by Shaw are Caesar and Cleopatra (1901), a historical play filled with allusions to modern times, and Androcles and the Lion (1912), in which he exercised a kind of retrospective history and from modern movements drew deductions for the Christian era. In Major Barbara (1905), one of Shaw's most successful «discussion» plays, the audience's attention is held by the power of the witty argumentation that man can achieve aesthetic salvation only through political activity, not as an individual. The Doctor's Dilemma (1906), facetiously classified as a tragedy by Shaw, is really a comedy the humour of which is directed at the medical profession. Candida (1898), with social attitudes toward sex relations as objects of his satire, and Pygmalion (1912), a witty study of phonetics as well as a clever treatment of middle-class morality and class distinction, proved some of Shaw's greatest successes on the stage. It is a combination of the dramatic, the comic, and the social corrective that gives Shaw's comedies their special flavour.