E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A political term first employed in 1815, when Lord Byron and his friends set on foot the periodical called The Liberal, to represent their views in politics, religion, and literature. The word, however, did not come into general use till about 1831, when the Reform Bill, in Lord Greys Ministry, gave it prominence.
Influenced in a great degree by the philosophy and the politics of the Continent, they [the Whigs] endeavoured to substitute cosmopolitan for national principles, and they baptised the new scheme of politics with the plausible name of Liberalism.Disraeli, June 24, 1872.