In the 1760s, an alternative vision of party emerged: Edmund Burke’s party of principle. This chapter considers the formation of Burke’s party, the Rockingham Whigs, in the context of George III’s accession to the throne and the conclusion of the Seven Years’ War. Burke’s close friend and writing collaborator William Burke introduced him to the circle of the Marquess of Rockingham, and when Rockingham took office as First Lord of the Treasury in July 1765, Burke became his private secretary. At the end of that year, Burke was elected as MP for Wendover and in the following years he emerged as the leading publicist of the Rockingham Whigs. This chapter considers Burke’s early writings in service of his party, especially his understudied Observations on a Late State of the Nation (1769).