Charaxes jasius, the two-tailed pasha, is a butterfly in the family Nymphalidae. It is the only European species of the genus Charaxes. Divergence of the Mediterranean species C. jasius from the last common ancestor with its closest related species still flying in the Afrotropical realm most probably occurred around 2 mya, i.e. during the Pliocene.

The rajah and pasha butterflies, also known as emperors in Africa and Australia, make up the huge type genus of the brush-footed butterfly subfamily Charaxinae, or leafwing butterflies. They belong to the tribe Charaxini, which also includes the nawab butterflies (Polyura). Charaxes are tropical Old World butterflies, with by far the highest diversity in sub-Saharan Africa, a smaller number from South Asia to Melanesia and Australia, and a single species in Europe. They are generally strong flyers and very popular among butterfly collectors.