In the nineteenth century, Britain's need for overseas and imperial postal communications influenced the development of shipbuilding technology and the economics of shipping. When steamships were able to cross oceans, entrepreneurs sought government subsidies. Mail contracts favored the P&O line on the route to India and the Cunard line across the Atlantic. Subsidies encouraged the development of new technologies such as iron and steel hulls and propellers. Yet they were the object of friction between the Post Office, the Admiralty, the East India Company, and other branches of government. By the end of the century, it was clear that mail contracts and subsidies served Britain's prestige and national defense as much as its overseas postal communications.