Scholars do not believe that Ibn Battuta visited all the places he described and argue that in order to provide a comprehensive description of places in the Muslim world, he relied on hearsay evidence and made use of accounts by earlier travellers. For Example, it is considered very unlikely that Ibn Battuta made a trip up the Volga River from New Sarai to visit Bolghar and there are serious doubts about a number of other journeys such as his trip to Sana'a in Yemen, his journey from Balkh to Bistam in Khorasan and his trip around Anatolia. Ibn Battuta's claim that a Maghrebian called "Abu'l Barakat the Berber" converted the Maldives to Islam is contradicted by an entirely different story which says that the Maldives were converted to Islam after miracles were performed by a Tabrizi named Maulana Shaikh Yusuf Shams-ud-din according to the Tarikh, the official history of the Maldives. Some scholars have also questioned whether he really visited China. Ibn Battuta may have plagiarized entire sections of his descriptions of China lifted from works by other authors like "Masalik al-absar fi mamalik al-amsar" by Shihab al-Umari, Sulaiman al-Tajir, and possibly from Al Juwayni, Rashid al din and an Alexander romance and Ibn Battuta and Marco Polo's writings share extremely sections and themes, and some of the same commentary, it is also unlikely that the 3rd Caliph Uthman ibn Affan had someone with the exact identical name in China who was encountered by Ibn Battuta. However, even if the Rihla is not fully based on what its author personally witnessed, it provides an important account of much of the 14th-century world. Sex slaves were used by Ibn Battuta such as in Delhi. He wedded and divorced women and had children to sex slaves in Malabar, Delhi, and Bukhara. Ibn Battuta insulted Greeks as "enemies of Allah", drunkards and "swine eaters", while at the same time in Ephesus he purchased and used a Greek girl who was one of his many slave girls in his "harem" through Byzantium, Khorasan, African, and Palestine. It was two decades before he again returned to find out what happened to one of his wives and child in Damascus.