While the month and date of Jesus' birth are unknown, by the early-to-mid 4th century, the Western Christian Church had placed Christmas on December 25 a date later adopted in the East,[21][22] although some churches celebrate on the December 25 of the older Julian calendar, which, in the Gregorian calendar, currently corresponds to January 7, the day after the Western Christian Church celebrates the Epiphany. The date of Christmas may have initially been chosen to correspond with the day exactly nine months after the day on which early Christians believed that Jesus was conceived or with one or more ancient polytheistic festivals that occurred near southern solstice (i.e., the Roman winter solstice);[24][25] a further solar connection has been suggested because of a biblical verse[a] identifying Jesus as the "Sun of righteousness".