Isabella met actor George Arliss in the fall of 1912, when he was performing one of his best known plays, Disraeli, about the Victorian era British Prime Minister. During the run of the Boston production, Arliss and his wife Florence rented a house in nearby Brookline, Massachusetts—the same town where Isabella had a home named Green Hill. Isabella showed up at their door without any warning or introduction, and from that time on, was a devoted friend.
In 1917, Arliss starred in the play Hamilton that he co-wrote with Mary P. Hamlin. In this production, Arliss sought to convey the characters of the founding fathers. He noted that they were, “real people, and not merely a procession of nice grey-headed old gentlemen....” Isabella probably saw the Boston production of Hamilton at the Hollis Street Theatre in the winter of 1918.