John III Doukas Vatatzes
In the report, he described the peculiarities of the Mongol Empire as well as many geographical observations. There were also anthropological observations, such as his surprise at the presence of Islam in Inner Asia. William was critical of the Hellenic traditions he encountered among the Christians of the former Byzantine Empire, including the Nicaean celebration of a feast day for Felicitas, which he reports was known to John III Doukas Vatatzes through the alleged possession of the second half of Ovid's incomplete Book of Days.