In the early part of the 20th century Roser and his wife, Ruth, arrived in St. Petersburg where he built several hotels downtown as well as an office building and cafeteria on Central Avenue. He opened his C. M. Roser Real Estate office at 695 Central Avenue in the building he had built. Roser also built and donated a nurse's home for Mound Park Hospital as well as the first building for Mercy Hospital.[1]