The Persians apparently hoped that the British would not contest their acquisition of Herat -- they recognised that they could not expect to win a war against the British army -- and thus once British opposition became clear they attempted to back down. Negotiations in Constantinople between Persian ambassador Ferukh Khan and British ambassador Lord Stratford de Redcliffe ultimately broke down over British demands that the Persians replace their prime minister (the sadr-i a'zam). News of the onset of fighting resulted in a formal rupture of talks, but discussions soon began again in Paris, and the two sides signed a peace treaty on 4 March. In the treaty, the Persians agreed to withdraw from Herat, to apologise to the British ambassador on his return, to sign a commercial treaty, and to cooperate in suppressing the slave trade in the Persian Gulf; the British agreed not to shelter opponents of the Shah in the embassy, and they abandoned the demand to replace prime minister as well as one requiring territorial concessions to the Imam of Muscat, a British ally.'