in Mexico City. Modotti's visual vocabulary matured during this period, such as her formal experiments with architectural interiors, blooming flowers, urban landscapes, and especially in her many beautiful images of peasants and workers during the depression. In 1926, Modotti and Weston were commissioned by Anita Brenner to travel around Mexico and take photographs for what would become her influential book Idols Behind Altars. The relative contributions of Modotti and Weston to the project has been debated. Weston's son Brett, who accompanied the two on the project, indicated that the photographs were taken by Edward Weston. In 1925, Modotti joined International Red Aid, a Communist organization. In November 1926, Weston left Mexico and returned to California. During this time Modotti met several political radicals and Communists, including three Mexican Communist Party leaders who would all eventually become romantically linked with her: Xavier Guerrero, Julio Antonio Mella, and Vittorio Vidali. Starting in 1927, a much more politically active Modotti (she joined the Mexican Communist Party that year) found her focus shifting and more of her work becoming politically motivated. Around that time her photographs began appearing in publications such as Mexican Folkways, Forma, and the more radically motivated El Machete, the German Communist Party's Arbeiter-Illustrierte-Zeitung (AIZ), and New Masses. Mexican photographer Manuel Álvarez Bravo divided Modotti's career as a photographer into two distinct categories: "Romantic" and "Revolutionary", with the former period including her time spent as Weston's darkroom assistant, office manager and, finally, creative partner. Her later works were the focus of her one-woman retrospective exhibition at the National Library in December 1929, which was advertised as "The First Revolutionary Photographic Exhibition In Mexico". Life as an activist Modotti began a relationship with Xavier Guerrero, who was a member of the Mexican Communist Party, in 1927. Guerrero was sent to Moscow for a year to take part in political party training, and by 1928 Modotti had met and begun a relationship with the exiled Cuban activist Julio Antonio Mella. During this same period, economic and political conflicts within Mexico and indeed much of Central and South America were intensifying and this included increased repression of political dissidents. In 1929, Mella was assassinated while walking in the street with Modotti from the offices of Red Aid, a Comintern-attached organization that offered relief to and defended victims of political repression. Modotti was immediately arrested, but later released and cleared of his murder. Shortly thereafter,