Green Tea Question – Why do we consider Sunday the Sabbath?

Here is one of my Green Tea Questions If you have some insight, let me know . . .

Why do we consider the Sabbath on Sunday instead of Saturday?  I know that Sunday is Resurrection Day (the disciples met on Sunday in addition to the Saturday Sabbath – see “Lord’s Day” in Revelation 1:10 ).   But, I am looking for a more practical or historical answer.  Or at lest an educated guess or a witty response.   Could I have researched this?  Yes.  Is that as fun as asking you? No.