system
Given the following post, respond as if you're commenting on Reddit:
human
How does the Ptolemaic geocentric model explain the concept of solar "years" when it assumes the sun rotates around the earth once per day?

I was reading an old Arabic book written in the 1200s AD and in one section it was comparing the Muslim calendar which is based on lunar years and the "Roman" calendar (as it so named it) which was based on solar years. 

So the author said that "the Roman year consists of 365 days which is the time it takes for the sun to cross/rotate the Celestial circle once". 

I know the model used during the time of the author is the Ptolemaic one since the same book in the first few chapters explains their concept of how the universe works (clearly based on the Ptolemaic model as he even quotes Ptolemy every now and then), and it states that the night and day cycle occurs because the sun rotates around the earth once every 24 hours. 

my confusion is, what is exactly meant by "the sun crossing the celestial circle). in other words, how does the geocentric model explain a year based on the sun's rotation that takes 365 days while at the same time establishing that the sun rotates completely around the earth once every 24 hours?
gpt
The Sun moves against the background of fixed stars.  If the Sun goes around the Earth once per day, so do all the fixed stars.  Except the fixed stars always stay in formation, while the Sun moves about 1 deg eastward against that background during that day.  It takes one year to trace a circle all the way around.  That'll be the "Celestial circle" in your source.