“By liberty I mean the assurance that every man shall be protected in doing what he believes his duty against the influence of authority and majorities, custom and opinion.”
The History of Freedom in Antiquity (1877), p.3
Help us to complete the source, original and additional information
John Dalberg-Acton, 1st Baron Acton 112
British politician and historian 1834–1902Related quotes

The Divorce of Catherine of Aragon http://books.google.com/books?id=Y1wLAAAAYAAJ&q="The+first+duty+of+an+historian+is+to+be+on+his+guard+against+his+own+sympathies+but+he+cannot+wholly+escape+their+influence"&pg=PA19#v=onepage (1891)

Trial of John Vint and others (1799), 27 How. St. Tr. 640.

“What do I believe? As an American I believe in generosity, in liberty, in the rights of man.”
Essay in This I Believe : 2 (1952) edited by Edward R. Murrow, p. 142
Context: What do I believe? As an American I believe in generosity, in liberty, in the rights of man. These are social and political faiths that are part of me, as they are, I suppose, part of all of us. Such beliefs are easy to express. But part of me too is my relation to all life, my religion. And this is not so easy to talk about. Religious experience is highly intimate and, for me, ready words are not at hand. I am profoundly aware of the magnitude of the universe, that all is ruled by law, including my finite person. I believe in the infinite wisdom that envelops and embraces me and from which I take direction, purpose, strength.
Preface to The Story of the Stone, Vol. 2: 'The Crab-Flower Club' (1979), p. 20

Federalist No. 10
1780s, Federalist Papers (1787–1788)

Speech in the House of Commons on the gun-running at Larne, Ireland (27 April 1914), quoted in The Times (28 April 1914), p. 8
Prime Minister

“England expects every Man will do his Duty.”
Famous signal to the British fleet before the battle of Trafalgar, as quoted in Life of Nelson, Ch. 9; Initially dictated as: "England confides that every man shall do his duty." The signaller pointed out that "expects" was in the signals alphabet, but "confides" was not and so had to be spelt out, taking longer, and Nelson agreed to the change.
Variant:
England expects every officer and man to do his duty this day.
As reported in The London Times (26 December 1805)
The Battle of Trafalgar (1805)

Other writings, The Paradoxes of Legal Science (1928)

The Relation of the State to the Invididual (1890)