So it depends on what calendary you use here? So, if in your culture, your calendar shows the week starting on Monday, the seventh day on the calendar is Sunday and therefore the Sabbath day is Sunday.
In several languages, the name of Sunday is associated with The Lord, identifying Sunday as the holy day of the week.
Saturday is associated with Sabbath in several languages. So, what's your point? Sun day was a worship day with sun worshipers. This was a large group at one time.