How do the Amazons have children? 

Historical sources claim the Amazons would only concede to sporadic intercourse with the captured representatives of neighboring peoples. For Penthesilea, Heinrich von Kleist therefore imagined a "Rosenfest" (rose festival) as an annual springtime fête in which the rose-crowned Amazons abandon themselves to these enemy men captured in battle. The site of this rose festival is the city of Themiskyra, of the same-named, rose-covered plain which was the homeland of the Amazons. Themiskyra thus becomes a site of yearning in which war and hate change into love and fleeting happiness.

Kleist was probably inspired by Charles-Simon Favart's comic opera "La Rosière de Salency," a 1779 German version of which ("Das Rosenfest von Salenzi") was staged in Berlin, Breslau and other cities to great success. In turn, Favart's work referred to the actual fête de la rose tradition of Salency, a hamlet in the region of Picardy, France. Once every year, a so-called rosière (rose-girl) was elected and crowned with a wreath of the flowers, given a cash dowry, then allowed to select her future husband during the accompanying festivities.

Source: Appelt/Nutz, Erläuterungen und Dokumente Heinrich von Kleist, Penthesilea, 2001, S. 21 und 50