The Allan Shipping Line was started in 1819, by Captain Alexander Allan of Saltcoats, Ayrshire, trading and transporting between Scotland and Montreal, a route which quickly became synonymous with the Allan Line. By the 1830s the company had offices in Glasgow, Liverpool and Montreal. All five of Captain Allan's sons were actively involved with the business, but it was his second son, Sir Hugh Allan, who spearheaded the second generation. In 1854, Hugh launched the Montreal Ocean Steamship Company as part of the Allan Line, and two years later ousted Samuel Cunard to take control of the Royal Mail contract between Britain and North America. By the 1880s, the Allan Line was the world's largest privately owned shipping concern.

Captain Alexander "Sandy" Allan, was the Scottish sea captain and businessman who founded the Allan Shipping Line in 1819. Rising from shoemaker to shipping magnate in little more than thirty years, Allan retired in 1839 having made a fortune and created a transatlantic dynasty. He is recognised as one of the major contributors to Scotland's commercial interests in the early 19th century, and to the establishment of the Firth of Clyde as an international centre of shipping. During the Napoleonic Wars his brig Jean – so named for his wife – held the record for the fastest crossing between the Firth of Clyde and Quebec City. Under his five sons, the Allan Line became the world's largest privately owned shipping empire.