From the longer Wikipedia page [1]
The Liberal Unionist Party was a British political party that was formed in 1886 by a faction that broke away from the Liberal Party. Led by Lord Hartington (later the Duke of Devonshire) and Joseph Chamberlain, the party formed a political alliance with the Conservative Party in opposition to Irish Home Rule. The two parties formed a coalition government in 1895 but kept separate political funds and their own party organisations until a complete merger was agreed in May 1912.
The Liberal Democrat History Group page is [2].