Now, as the apostasy of the church at Rome spread throughout the empire, there did appear the usage of the 'lords day' but it was from another origin, and this is where we see it today in many peoples minds. Here is a great explanation from my buddy Amo..
'As we have already noted, excepting for the Roman and Alexandrian Christians, the majority of Christians were observing the seventh-day Sabbath at least as late as the middle of the fifth century [A.D. 450]. The Roman and Alexandrian Christians were among those converted from heathenism. They began observing Sunday as a merry religious festival in honor of the Lord's resurrection, about the latter half of the second century A.D. However, they did not try to teach that the Lord or His apostles commanded it. In fact, no ecclesiastical writer before Eusebius of Caesarea in the fourth century even suggested that either Christ or His apostles instituted the observance of the first day of the week.
"These Gentile Christians of Rome and Alexandria began calling the first day of the week 'the Lord's day.' This was not difficult for the pagans of the Roman Empire who were steeped in sun worship to accept, because they [the pagans] referred to their sun-god as their 'Lord.' "--EM. Chalmers, "How Sunday Came Into the Christian Church," p. 3.
Certain historians agree that it was the pagan sun-worshipers--and not Christians--who first gave the name 'Lord's day' to Sunday. "The first day of each week, Sunday, was consecrated to Mithra [the most widely known sun-god of the early Christian centuries] since times remote, as several authors affirm. Because the Sun was god, the Lord par excellence, Sunday came to be called the 'Lord's day,' as later was done by Christianity."--Agostinho de Almeida Paiva, 0 Mitraiomo, p. 3.
In Revelation 1:10 we are told of "the Lord's Day," but we are not there told which day of the week this is. Else where in Scripture the "Lord's Day" is clearly explained: only the Seventh-day Sabbath is His day (Ex 16:23,25; 20:10; 31:15; 35:2; Lev 23:3; Deut 5:4; Isa 58:13; Matt 12:8 and Mark 2:28). But it was pope Sylvester, Bishop of Rome (314- 337 A.D.--the "pope" during the reign of Constantine) who officially called Sunday the "Lord's Day." "He officially changed the title of the first day, calling it the 'Lord's Day' "--M. Ludovicum Lucium, Historia Ecclesiastica, "Century IV," chap. 10. pp. 739-740, Edition Basilea, 1624.
"The keeping of the Sunday rest arose from the custom of the people and the constitution of the Church . . . Tertullian [155-225 A.D.] was probably the first to refer to a cessation of affairs on the Sunday; the Council of Laodicea [337 A.D.] issued the first conciliar church council] legislation for that day; Constantine I [321 A.D.] issued the first civil legislation."--Vincent J. Kelly, Forbidden Sunday and Feast-day Occupations, 1943, p. 203. [Kelly is an American Catholic priest of the Redemptorist order].
Though Sunday is mentioned in so many different ways during the second century, it is not till we come almost to the close of the second, century that we find the first; instance in which it is called “Lord’s day."
Hmm... I think we can see how it came about into use and from where..
'As we have already noted, excepting for the Roman and Alexandrian Christians, the majority of Christians were observing the seventh-day Sabbath at least as late as the middle of the fifth century [A.D. 450]. The Roman and Alexandrian Christians were among those converted from heathenism. They began observing Sunday as a merry religious festival in honor of the Lord's resurrection, about the latter half of the second century A.D. However, they did not try to teach that the Lord or His apostles commanded it. In fact, no ecclesiastical writer before Eusebius of Caesarea in the fourth century even suggested that either Christ or His apostles instituted the observance of the first day of the week.
"These Gentile Christians of Rome and Alexandria began calling the first day of the week 'the Lord's day.' This was not difficult for the pagans of the Roman Empire who were steeped in sun worship to accept, because they [the pagans] referred to their sun-god as their 'Lord.' "--EM. Chalmers, "How Sunday Came Into the Christian Church," p. 3.
Certain historians agree that it was the pagan sun-worshipers--and not Christians--who first gave the name 'Lord's day' to Sunday. "The first day of each week, Sunday, was consecrated to Mithra [the most widely known sun-god of the early Christian centuries] since times remote, as several authors affirm. Because the Sun was god, the Lord par excellence, Sunday came to be called the 'Lord's day,' as later was done by Christianity."--Agostinho de Almeida Paiva, 0 Mitraiomo, p. 3.
In Revelation 1:10 we are told of "the Lord's Day," but we are not there told which day of the week this is. Else where in Scripture the "Lord's Day" is clearly explained: only the Seventh-day Sabbath is His day (Ex 16:23,25; 20:10; 31:15; 35:2; Lev 23:3; Deut 5:4; Isa 58:13; Matt 12:8 and Mark 2:28). But it was pope Sylvester, Bishop of Rome (314- 337 A.D.--the "pope" during the reign of Constantine) who officially called Sunday the "Lord's Day." "He officially changed the title of the first day, calling it the 'Lord's Day' "--M. Ludovicum Lucium, Historia Ecclesiastica, "Century IV," chap. 10. pp. 739-740, Edition Basilea, 1624.
"The keeping of the Sunday rest arose from the custom of the people and the constitution of the Church . . . Tertullian [155-225 A.D.] was probably the first to refer to a cessation of affairs on the Sunday; the Council of Laodicea [337 A.D.] issued the first conciliar church council] legislation for that day; Constantine I [321 A.D.] issued the first civil legislation."--Vincent J. Kelly, Forbidden Sunday and Feast-day Occupations, 1943, p. 203. [Kelly is an American Catholic priest of the Redemptorist order].
Though Sunday is mentioned in so many different ways during the second century, it is not till we come almost to the close of the second, century that we find the first; instance in which it is called “Lord’s day."
Hmm... I think we can see how it came about into use and from where..