 The Russo-Japanese War is also remembered in Matsuyama because of the contributions of two Japanese military leaders, the Akiyama brothers, Akiyama Saneyuki and Akiyama Yoshifuru, who were born in the city.In the twentieth century, various mergers joined the castle town with neighboring Dōgo, Mitsuhama, and other townships, aided by urban sprawl, creating a seamless modern city that now ranks as the largest in Shikoku.As of the most recent merger, on October 1, 2018, absorbing the city of Hōjō, and town of Nakajima (from the former Onsen District), the city had an estimated population of 510,963 and a population density of 1,196 persons per km².