The Lichfield House Compact was an agreement between the Whig government, the Catholic Party and the Radicals to act as one body against the Conservative Party. It was signed in February 1835 and this was how Daniel O'Connell managed to pass more reforms for Ireland.
The Compact has been argued by historians such as Robert Stewart[1] to have been the moment of formation of the Liberal Party. However, the Compact was formed in opposition to the Peelite faction, and some argue that it was the Peelites whose contribution to Liberal ideology played a dominant role in later years.
The House Compact was one of the reasons that Sir Robert Peel was able to return to power as many voters saw the alliance as dangerous.