What was the original purpose of the Castel Sant’Angelo?

Here is the question :

WHAT WAS THE ORIGINAL PURPOSE OF THE CASTEL SANT’ANGELO?

Here is the option for the question :

• Prison
• Fortress
• Mausoleum
• Museum

The Answer:

And, the answer for the the question is :

Explanation:

[STC006335] Built in the second century, Castel Sant’Angelo has served many purposes over its long history, including a prison, a fortress, and a possible refuge for the Pope. Nonetheless, it was originally constructed as a mausoleum for Hadrian and his family to be interred there. Since 1870, it has been used as a museum, displaying medieval weapons on one floor and Renaissance artifacts on another.