On this day in the year 321, Constantine decreed “the day of the sun” as a day of rest.

Roman Emperor Constantine I, known in history as Constantine the Great, may be considered one of the most influential rulers of antiquity, and can claim the greatest impact on modern society of any Roman leader. For it was Constantine who was instrumental in converting the Roman Empire to Christianity, and who therefore shaped the cultural and religious destiny of Europe and beyond.

His adoption of the Christian faith during his thirty-year reign as Emperor is shrouded in mystery. He did not declare himself a Christian until a relatively advanced age, and was supposedly only baptised on his deathbed. But his leadership was defined by a gradual process of accommodating and promoting the religion that had for so long been oppressed.

In 313, Constantine made a hugely significant pronouncement, in the Edict of Milan, that stated citizens should be allowed to practice the religion of their choice, and specifically banned the subjugation of Christian worshippers. The announcement was backed up by direct action, as the Roman government returned property to the Church that had been confiscated under previous regimes.

From this point on, Constantine became a great patron of the Church, diverting vast sums to church-building projects and defending the rights of Christians. Although the Roman Empire continued to be dominated by polytheist tradition for many years, the hegemony of polytheism was challenged, enabling the Christian faith to gain a foothold, and eventually leading to the supremacy of the Christian faith over polytheism.

The gradual process towards Christian tradition and ritual was underscored in 321, when, on the 7th of March, Constantine decreed that dies Solis, or “the day of the sun,” should be observed as a universal day of rest. The pious observance of the Sabbath was important in expressing thanks for God’s toil. Previously all Christian’s worshiped on Saturday the Seventh day of the week.

Constatine’s Edict

On the venerable day of the sun let the magistrate and people residing in cities rest, and let all workshops be closed. In the country however, persons engaged in agricultural work may freely and lawfully continue their pursuits; because it often happens that another day is not so suitable for grain growing or for vine planting; lest by neglecting the proper moment for such operations the bounty of heaven should be lost. —Schaff’s History of the Christian Church, vol. III, chap. 75.


The decree was far-reaching, stating that numerous activities should be avoided on Sunday. Merchants were forbidden to trade, and administrative establishments were closed, apart from those that dealt with the freeing of slaves. Farmers alone were permitted to continue working on the Sabbath, in recognition that some farm activity was impossible to defer.

Constantine chose Sunday to be the day for Christian worship as it already enjoyed special status in the Roman week. Named after the Pagan Sun God Invictus, Sunday had become the day when wages were traditionally paid to workers, leading it to be seen as a day of celebration and thanks. In corresponding the Christian Sabbath with an already established day of rest, Constantine ensured that his decree would be accepted swiftly and harmoniously.

In all major Christian denominations, Sunday continues to be observed as a holy day, remaining the day of choice for church attendance. For other religions the Sabbath still  falls on  Saturday a and for many, Sundays are seen as normal working days.