His 1928 mural In the Arsenal was interpreted by some as evidence of Rivera's prior knowledge of the murder of Julio Antonio Mella allegedly by Stalinist assassin Vittorio Vidale. After divorcing Guadalupe (Lupe) Marin, Rivera married Frida Kahlo in August 1929. Also in 1929, the first English-language book on Rivera, American journalist Ernestine Evans. The Frescoes of Diego Rivera, was published in New York. In December, Rivera accepted a commission to paint murals in the Palace of Cortez in Cuernavaca from the American Ambassador to Mexico. In 1928 his third child was born, Ruth. This year was also when he divorced Lupe Marin. He then later broke off and collaborated with Pablo Picasso in art. That same year Frida Kahlo met Diego Rivera with the hope that he’d be willing to give her advice on how to better her work and if any positive comments he had to say about her work. Although Diego was married at the time, they both instantly showed the interest of one another. They were married in 1929. Beside the age difference between them, and the disapproval of Frida’s parents who referred to the weds as the dove and the elephant, both their relationship and careers