Set Date for CJirist's Birth in Fourth Century Strangely, no one knows the exact date of the birth of Christ. Until some time in the Fourth century, Christmas (Christ's Mass) was variously vari-ously celebrated on January 6, February Feb-ruary 2. March 25, April 19, May 20 and November 17. In 1644, the English Eng-lish parliament passed an act forbidding for-bidding the observance of Christmas. Christ-mas. Later Charles II revived the Feast, as Christmas then was called.