Christianity came to North Africa in the Roman era. According to historian Theodor Mommsen what is now Mediterranean Algeria was fully Christian by the fifth century. A notable Berber Christian of Algeria was Saint Augustine (and his mother Saint Monica), important saints of Roman Catholicism. Christianity's influence declined during the chaotic period of the Vandal invasions but was strengthened in the succeeding Byzantine period. After the Arab invasions of the 7th century, Christianity began to gradually disappear.