beginning a siege that would last until 1387. Meanwhile, Andronikos IV died and his son, John VII, began quarreling with his grandfather, John V. With Thessalonica surrendering in 1387 and his position rather hopeless, Manuel returned to John V and, with the Sultan's assent, began making conciliatory offers to his father. John V realized that accepting his second son back would cause his grandson to rebel in turn, and therefore he simply kept Manuel in exile in Lemnos. Eventually, John VII did rebel against his grandfather — news of Manuel's arrival at Constantinople and John V's reconciliation talks with him prompted John VII to head to Genoa and then to the new Ottoman Sultan, Bayezid the Thunderbolt, to seek aid in order to topple John V. John VII's rebellion succeeded initially, taking Constantinople from John V, but Manuel countered by rousing the rest of the empire and its few remaining military assets and turned them against John VII. Manuel also received aid from the Knights of St. John stationed at Rhodes, where he "donated" religious relics made of precious metals to them for their support. John refused to give up his right to rule as Emperor of Byzantium until his death in 1408. By then however, the Ottoman Sultan Bayezid had recognized Manuel II Palaiologos as co-emperor of Byzantium alongside his father John V, and finally, when John V died in 1391, as sole Emperor. Manuel II Palaiologos, 1391–1420 Manuel II's reign saw another temporary respite for the Byzantines. For an Empire in such trouble, he succeeded in retaking some territory and held it to the end of his reign. His limited success largely came through the resurrection of Mongol Power in the East and the great friendship achieved between Manuel II and Mehmed I. However, he lived long enough to see his son undo much of his achievements. Vassalage to 1394 Manuel II's first priority was to establish an agreement with Bayezid I. John VII was a favorite of Bayezid so Manuel II was in a dangerous position. He eventually sealed an agreement. However, the Ottoman Sultan became infuriated by Manuel II's attempts to reconcile his nephew John VII. Manuel was concerned that John VII might once again launch a coup against him so wished to end the threat diplomatically. Bayezid ordered Manuel's execution, but then reduced his furious response and instead demanded that Constantinople build another Mosque and