Initial incursions across the Oxus river were aimed at Bukhara (673) and Samarqand (675) and their results were limited to promises of tribute payments.[102] In 674, a Muslim force led by Ubaidullah Ibn Zayyad attacked Bukhara, the capital of Soghdia, which ended with the Sogdians agreeing to recognize the Umayadd caliph Mu'awiaya as their overlord and to pay tribute.[2] In general, the campaigns in Central Asia were "hard fought" with the Buddhist Turkic peoples fiercely resisting efforts to incorporate them into the caliphate.