Conversion to Christianity

=== Coercion ===
While Christian theologians, such as the fourth century Augustine and the ninth century Alcuin, have long maintained that conversion must be voluntary, there are [[Forced conversion#Christianity|historical examples of coercion]] in conversion to Christianity.{{sfn|Allott|1974|p=72}}{{sfn|Brown|1963|pp=107-116}} Constantine used both law and force to eradicate the practice of sacrifice and repress heresy though not specifically to promote conversion.{{sfn|Leithart|2010|p=302}}{{sfn|Lim|2012|p=498}} Theodosius also wrote laws to eliminate heresies, but made no requirement for pagans or Jews to convert to Christianity.{{sfn|Brown|1963|p=286}}{{sfn|Sáry|2019|pp=72-74, 77}}{{sfn|Hebblewhite|2020|loc=chapter 8|p=82}} However, the sixth century Eastern Roman emperor [[Justinian I]] and the seventh century emperor [[Heraclius]] attempted to force cultural and religious uniformity by requiring baptism of the Jews.{{sfn|Kaldellis|2012|p=3}}{{sfn|Irmscher|1988|p=166}}{{sfn|Sharf|1955|pp=103-104}}{{sfn|Lichtenberger|Raja|2018|pp=85–98}} In 612, the Visigothic [[Sisebut|King Sisebut]], prompted by Heraclius, declared the obligatory conversion of all Jews in Spain.{{sfn|García-Arenal|Glazer-Eytan|2019|pp=5–6}} In the many new nation-states being formed in Eastern Europe of the [[Late Middle Ages]], some kings and princes pressured their people to adopt the new religion.{{sfn|Štefan|2022|p=101}} And in the [[Northern crusades]], the fighting princes obtained widespread conversion through political pressure or military coercion even though the theologians continued to maintain that conversion must be voluntary.{{sfn|Fonnesberg-Schmidt|2007|p=24}}