Question

why did female figure became allegory​

Answer 1

Answer:

The female figure was chosen to personify the nation did not stand for any particular woman in real life. ... Thus the female figure became an allegory of the nation. During the French Revolution artists used the formal allegory to portray idea such as Liberty Justice and the Republic.

Answer 2

During 19th century, artist started to personify the nation. Female figures were choose to represent the nation. The female figures didn't come from any society of real life, rather they gave a concrete form to the nation. Thus the female figures became an allegory of nation.