Historians are divided over when Islam came to Mexico and who brought it. Some claim it was introduced by Syrian immigrants, whereas others point to Turkish immigrants. One recent (2002) study estimated that 10 percent of the Syrian-Lebanese immigrant community were Muslim. Today this community is one of the richest and contains more than 250,000 people. The history of Islam in Mexico is largely undocumented, with the exception of a sixteenth-century book called Un Hereje y un Musulman. Written by Pascual Almazan, this recounts the exploits of Yusuf bin Alabaz, who came to Mexico after expulsion during the Reconquista in Spain. Today, Islam is a recognized entity following the establishment of the Muslim Center de Mexico in 1994 in Mexico City. There are also centers in Monterrey, Torreon, Guadalajara, and San Cristobal de las Casas.