Although this term appears nowhere, it has been conjectured that a declaration of Christianity as "illicita" was the legal basis for official persecutions. There was, however, "no law, either existing section of criminal law, or special legislation directed against the Christians, under which Christians were prosecuted in the first two centuries." Rome lacked a uniform policy or legal code pertaining to foreign cults, and before Christian hegemony in the 4th century, there was no legal language to designate a concept analogous to "heresy" or crimes against orthodox religion. Some scholars have argued that Christianity was declared a "religio illicita" (an impermissible or illegitimate religion) by Nero following the Great Fire of Rome in 64.