What is Aelia Capitolina?
The land that was originally the kingdoms of Israel and Judaea became in 63 BCE a client kingdom Judaea under Roman control. In 6 CE it became a province Judaea.
After several revolts the Romans, bent on destroying the association of the land with the people of Israel and their god, renamed Judaea "Syria Palestina" and Jerusalem "Aelia Capitolina". The first name, "Palestine", stuck. And even today there are those who call the land "Palestine" and who, at the same time, deny the connection of the land of Israel with the people of Israel.
The name "Palestine" was not mentioned in the Quran, as Muhammed was a G-d-fearing man who would not support the pagan attempt to take away the land of Israel from Allah. Instead the Quran speaks of the land as the land given to the people of Israel by Allah through Moses.
It was only after World War I that the name "Palestine" resurfaced. And like the last time Europeans, this time Christians, brought the name, naming what was once the kingdoms of Judaea, Israel, Edom, and Ammon "Palestine" again, officially the mandate territory of "Palestine (Land of Israel)". The term can be found on currency printed during the time.
During all that time the region had been inhabited by various Semitic tribes, including Jews, Arabs, Aramaeans, Phoenicians, and various sub-groups. Some are extant even today. Occasionally new groups emerged, like the Druze, a religious or ethnic group of a few hundred thousands living today in Israel, Lebanon, and Syria.
In 1948 what remained of "Palestine (Land of Israel)", after the part east of the Jordan had already been made into an Arab kingdom, was divided into a Jewish part, an Arab part, and an international part around Jerusalem.
Some of these terms now mean different things.
For example, once "Palestina" was a new name for a country that used to be called "Israel" (or Judaea). Today "Palestine" is the original name and "Israel" is the newcomer.
Once a "Palestinian" was an inhabitant of "Palestine". Today a "Palestinian" is only a non-Jewish inhabitant of "Palestine".
And once "Palestine" was the "Land of Israel", according to the British. Today "Palestine" was just "Palestine" and the currency that says "Land of Israel" is now used to prove that the land is not the "Land of Israel".
Ironically, the Arab name of Jerusalem is "Al-Quds", which translates to "The Holy" (QDS is the Semitic root for "holy"). The reason it's "holy" is because it used to house the temple of Allah. But in an interesting twist the city that was once holy to Muslims because it was the capital of the Land of Israel is now supposed to be the capital of a country named as the pagans wanted to name it.
Why not name it Aelia Capitolina again and be done with it?