C&O continued to be one of the more profitable and financially sound railways in the United States, and in 1963, under the guidance of Cyrus S. Eaton, helped start the modern merger era by "affiliating" with the Baltimore & Ohio. The two lines' services, personnel, motive power and rolling stock, and facilities were gradually integrated. Under the leadership of Hays T. Watkins Jr., in 1973 Chessie System was created as a holding company for the C&O, B&O and Western Maryland Railway. In effect, C&O formally adopted a nickname that had been used colloquially for the railroad for several years, after the mascot kitten used in ads since 1933.