From pages 79-95 The Life of Mark Twain - The Middle Years 1871-1891:
In May 1873 Samuel L. Clemens made good on his promise to escort Olivia to England. His purpose in returning was threefold: to introduce his wife to the mother country; to research his next travel book, a project that would soon be abandoned; and to secure imperial copyright on The Gilded Age, which had just been published in the United States. Joining the three Clemenses were Livy's Elmira friend Clara Spaulding, daughter Susy's nurse Nellie Bermingham, and Sam's personal secretary Samuel Thompson. On May 15 Sam led the party of six from Elmira to New York City. They were greeted there by Mary Mason Fairbanks, who overnighted with Livy in their cabin aboard ship while Sam slept at the St. Nicholas Hotel. ...
Sam sailed with his family on the Batavia, once again under the command of John Mouland. ...