sons, Süleyman Çelebi, in which the city of Thessalonica, as well as substantial territories in Thrace and Macedonia, were returned to the Byzantine Empire. John baptised and christianised two of Bayezid's sons in 1403: İsa Çelebi and Yusuf Çelebi. İsa may have been adopted by John, and Yusuf is recorded to have continued to live in Constantinople, attested there as late as 1413. Upon Manuel's return to Constantinople in June 1403, John returned power to him. Though some contemporary comments seem to suggest that everyone expected John VII to refuse to surrender power, John VII appears to have been content with letting go of his responsibilities after governing the Byzantine capital for three and a half years. Once Manuel returned, he reversed several of John VII's decisions, for instance disavowing a treaty John VII had arranged with the Ottomans, in which he had granted them religious and financial privileges. Further tensions within the imperial family After Manuel's return in 1403, relations between him and John VII were tense once more. Since he knew that John VII could no longer rely on the support of the Ottomans, Manuel attempted to completely exclude him from the imperial hierarchy, stripping him of the title basileus and depriving him of his promised lands in Selymbria and Thessalonica. The reasons for excluding John was attributed by Manuel to rumours that John had initiated negotiations in 1402 with Bayezid concerning the surrender of Constantinople. The contemporary Castilian traveller Ruy González de Clavijo wrote that John and Bayezid had agreed that should Bayezid defeat the Timurids, John would surrender the city. It is doubtful that such an agreement was ever made, especially since John proved himself to be loyal for the duration of his tenure as regent and concluded a highly favourable treaty with the Ottoman prince Süleyman Çelebi. According to German historian Peter Wirth, it is possible that the reason for resentment again brewing up between John and Manuel after Manuel's return could be that Manuel felt that he had been ignored and left out of these important negotiations. John was sent to the island of Lemnos, apparently in disgrace, but fled to his father-in-law Francesco on nearby Lesbos. Soon thereafter, in September 1403, John and Francesco launched a naval expedition against Thessalonica, though it appears to have had little to no result. The expedition was not some attempt to seize the city from Manuel's control,