Dictatress

[…] two things he promised her, and performed for her, which were tokens of a mercilesse heart, the balefull death of his son, and the chaunge of the state, in such sort that Aurelia Orestilla should be the Dictatresse of Rome.

Source: wiktionary

What Athens was in science, Rome in power, / What Tyre appeared in her meridian hour, / ’Tis thine at once, fair Albion, to have been, / Earth’s chief dictatress, ocean’s mighty queen:

Source: wiktionary

1821, John Quincy Adams, address delivered on 4 July, 1821, cited in Antony Jay (ed.), The Oxford Dictionary of Political Quotations, Oxford University Press, 1997, p. 4, America […] well knows that by once enlisting under other banners than her own […] she would involve herself beyond the power of extraction, in all the wars of interest and intrigue […] which assume the colours and usurp the standard of freedom. The fundamental maxims of her policy would insensibly change from liberty to force […] She might become dictatress of the world.

Source: wiktionary

1980, William L. Andrews, The Literary Career of Charles W. Chesnutt, cited in Thomas Votteler (ed.), Short Story Criticism, Farmington Hills, MI: Cengage Gale, Volume 7, 1991, p. 29, Wellington’s first wife does not belong among the overstuffed dictatresses of the white folks’ kitchen.

Source: wiktionary