In the summer of 1940, Frida Kahlo found herself in jail. Mexico City police suspected her as an accomplice in the murder of the embattled Russian revolutionary Leon Trotsky. Several days prior to her arrest, he’d been gruesomely offed with an ice pick. His murder—and her implication in the crime—was a dramatic turn of events, especially considering that Kahlo and Trotsky had been giddy lovers just three years earlier; she’d even dedicated a striking self-portrait to him.

Kahlo had many romantic partners over the course of her short life (she died in 1954 at 47), but few resulted in dedicated paintings—and fewer pointed explicitly to her political beliefs. The liaison with Trotsky did both. Although their romance only lasted several months, it offers a window into Kahlo’s politics and how deeply they influenced her work.

Kahlo and Trotsky first met in 1937, when the painter was 29 and the politician was 57. Kahlo and her husband, muralist Diego Rivera, were vocal supporters of Marxism and had been on-and-off members of the Mexican Communist Party for a decade, since 1927. Influenced by the Mexican Revolution at the turn of the century, they advocated for a populist government and believed political power should rest in the hands of the working class. In Rivera’s 1928 mural The Arsenal, he showed Kahlo as an activist. Wearing a shirt emblazoned with a red star (red being the traditional color of Communism), Kahlo disseminates weapons to workers while a flag bearing the Communist party’s hammer-and-sickle insignia flies over the scene.