7649.25 days? I think it has to be more than that. I get 7669, 7670, or 7671, depending on where the leap years fall, although 7669 is not applicable this century. Did you mean 7670.25 days?

You're right I was figuring on 364.25 days a year instead of 365.25.

Where did you pluck 364.25 days from?

"This was also evidenced because most all countries who had calendars changed to the 365.25 day calendar at about the same time." The Gregorian calendar, of which you seem to be referencing, was adopted by France, Italy, Poland, and Spain, in 1582. The next country to adopt it was Prussia, in 1611, nearly 30 years later. The next country, which was the first non-Catholic country to adopt the calendar was Denmark, in 1700, nearly 120 years after it's introduction in Italy. It wasn't until the late 1800's that the Gregorian calendar was widely accepted. I'd say that whoever wrote what you read was not well versed in factual history. Also, during all of recorded history, Mars has been the fourth planet. We can easily project that much further into the past, prior to our modern solar system model, because planets nearer to the sun than the earth experience phases like the moon does. You can see Venus and Mercury quite clearly in the sky, and, on a clear day with good eyes, you can see the phases of Venus without a telescope. Astronomical records of Mars going back thousands of years never indicate that it disappeared from the sky, as it would have in the new-mars phase, as Venus and Mercury do. I'd say that this entire explanation is something someone made up and expected no one to question logically.