Pantheon and the Universal Time

https://www.thelocal.it/20180501/facts-about-rome-pantheon

When I visited Pantheon  Jun 2006, I thought it is some way like  a big calender but how. What is the kea?

The Pantheon you see today is not the first structure on that site. The original temple was built as around 25 BC by Roman consul Marcus Agrippa, whose name you can still make out on the façade. Archaeologists now believe his version was destroyed and rebuilt, possibly more than once.

The building as it stands is generally attributed to Emperor Hadrian, who is thought to have had it redesigned and completed nearly 1,900 years ago.

“If you’re lucky enough to be inside the Pantheon on April 21st, around noon, look towards the entrance: you’ll see the sunlight that enters through the oculus hitting the door dead on.

April 21st is the date of the founding of Rome and historians suspect that the Pantheon may have been designed to give the emperor some gloriously symbolic backlighting as he entered the temple to celebrate the anniversary”.

21 april 753 BCE

Founding of the Rome 2771 years ago

( In my mind I thought that  the wise men  wanted to understand  the stability of universum with the help of sun ( perhaps even some  stars and  moon)  and   their  relationship  to one point on the   earth during ages, and that kind of building  is  a good help to mathematicians).