After the Labor landslide at the 1983 election, Keating was appointed Treasurer by Prime Minister Bob Hawke. He became one of the most influential figures in the Government, overseeing the introduction of a large number of reforms intended to liberalise and strengthen the Australian economy. These included the Prices and Incomes Accord, the float of the Australian dollar, the elimination of tariffs, the deregulation of the financial sector, and reform of the taxation system (including the introduction of capital gains tax, fringe benefits tax, and dividend imputation). After an initially close partnership, leadership tensions began to increase between Hawke and Keating, culminating in a secret agreement that Hawke would eventually retire in Keating's favour. Keating became Deputy Prime Minister in 1990, but in June 1991 he unsuccessfully challenged for the leadership, believing that Hawke had reneged on their earlier agreement. He resigned as Treasurer, but mounted a second successful challenge six months later.