In the autumn of 1922, Rivera participated in the founding of the Revolutionary Union of Technical Workers, Painters and Sculptors, and later that year he joined the Mexican Communist Party (including its Central Committee). His murals, subsequently painted in fresco only, dealt with Mexican society and reflected the country's 1910 Revolution. Rivera developed his own native style based on large, simplified figures and bold colors with an Aztec influence clearly present in murals at the Secretariat of Public Education in Mexico City begun in September 1922, intended to consist of one hundred and twenty-four frescoes, and finished in 1928.