The company's first major endeavor was its Liverpool Line, known as the Blue Swallowtail Line (1822–1880) from its distinctive blue and white swallowtailed house flag. This enterprise was originally started by Fish, Grinnell and Co. in cooperation with Thaddeus Phelps and was called the "Fourth Line of Liverpool Packets." The Blue Swallowtail line originally sailed monthly and, like the other Liverpool-New York packet lines, did a thriving business in the wave of Irish immigration in the wake of an Gorta Mor. Its ships included the "New World" (built 1846, and reported to be the largest merchant ship in the world at the time), "Queen of the West", "Henry Clay", "Ashburton", "Patrick Henry", "Roscoe", "American Union", and "Albert Gallatin". In 1851, the line expanded to eight regular packets sailing from Liverpool on the 6th and 21st of each month. In 1854, management divided between Cornelius Grinnell, who took over four ships, and the firm, which operated five ships, as before. The firm added nine more vessels before 1860, including the Packet "Aurora" (built 1854, 1,639 tons), with three decks and room for 1,000 passengers. This included the massive "Ontario" (built in 1855 at 1,501 tons burthen), which ran aground off of Holgate, Long Beach Island, New Jersey in 1876.