Harris demanded the courtesies due to an accredited envoy and refused to deliver his president's letter to anyone but the Shogun in Edo, and to him personally. After prolonged negotiations lasting 18 months, Harris finally received a personal audience with the Shogun in the palace. After another four months, he successfully negotiated the Treaty of Amity and Commerce, or the "Harris Treaty of 1858," securing trade between the US and Japan and paving the way for greater Western influence in Japan's economy and politics.