This song was written by a man who lived in the 10th and 11th century. So it certainly has been called Palestine for quite some time.
It doesn't matter who the original inhabitants were, there are ruins in Anatolia that predate the Turks, so does that mean the Greeks or Italians should lay claim to it? Since there is a history of them being there centuries before.
A friend of mine has just told me that Palestine (though not Palestinian) is mentioned, by that name, in the Old Testament. She's searching for it as we speak.
This is of course irrelevant, but, worth mentioning in this context.
And here she has it...
Sorrow of men of Palestina. Ex 15:14
Rejoice not thou whole Palestina. Isiah 14:29
Thou whole Palestina art dissolved. Isiah 14:31