They were one of the rivals for regional dominance with the ancient Israelites, along the east coast of the Mediterranean Sea. The Philistines, needless to say, were not an Arab people and were in no way the forebears of the Arabs who conquered the Land of Israel in the seventh century. Neither are they, of course, the children of the Canaanites, nor of the Jebusites, as Palestinian-Arab authorities sometimes claim.
The areas of Judea and Samaria, and all the land of Eretz Israel, was renamed Syria-Palestina by the Roman Emperor Hadrian in the year 70 AD for the explicit purpose of erasing Jewish history on the land of the defeated indigenous Jewish population.
From that day to this the traditional homeland of the Jewish people was generally referred to as either "Palestine" or the "Holy Land" or "Eretz Israel," including the regions of Judea and Samaria, depending upon among whom, when, and where the conversation is taking place.
By the time that the Zionist project began in earnest at the end of the nineteenth-century the terms "Palestine," to refer to the region, and "Palestinian," to refer to the Jews of the region, were commonplace.
As is often remarked, the Jerusalem Post was originally dubbed the "Palestine Post." And so and so forth. It was not until after the Jews relinquished the designation that the local Arabs picked it up. This is why Golda Meir could famously question what the hell is a Palestinian.
In this way, the idea of "Palestinian" to refer specifically to the local Arabs was born and with it, for the very first time in human history, an allegedly distinct ethnicity emerged for the specific purpose of robbing another people of sovereignty and self-defense on their own land.
In a certain kind of way, this answers the question of just what is a "Palestinian," anyway? You could put it like this:
A "Palestinian" is an Arab residing on Jewish land whose culture - and, thus, in some measure whose cultural identity - is wholly dependent upon the effort to eliminate Jewish autonomy and self-defense in Eretz Israel.
This definition, however, only makes sense if the Palestinian-Arabs do, in fact, represent a distinct ethnicity. While I understand, of course, about Benedict Anderson's criticisms of nations as "imagined communities," nonetheless for a distinct ethnic group to be a distinct ethnic group there must be significant cultural distinctions between that group and the larger related communities.
In the case of those whom we call "Palestinians" the distinctions are so minor as to be virtually invisible to non-Arabs. This is not the case between, for example, the Japanese and the Chinese because even non-Asians can readily observe the many cultural distinctions between these neighboring far eastern peoples. The "Palestinians," however, share the same cuisine with other Arabs. They share the same religion with other Arabs. They share the same language with other Arabs. They share similar honor / shame codes. Customs. Culture. Language. Food. Traditions.
All more or less the same.
The reason for this is because Palestinian-Arab nationalism was merely a response to the fact that the Jews had finally released themselves from dhimmitude and it would no longer allow ourselves to be forced into second and third-class non-citizenship under Arab-Muslim domination. Thirteen centuries was more than enough, thank you very much.
So, if "Palestinian" is not a distinct ethnicity than just what is a "Palestinian"?
The truth of the matter, of course, is that "Palestine" is simply another name for the Land of Israel, but one foisted upon it by a malicious Roman conqueror. Just as Jewish people have no moral obligation to recognize a "Palestinian" people who came into existence, as an allegedly distinct people, within recent decades for the specific purpose of doing Jewish people harm, so we have no compelling reason to resurrect the name "Palestine" to refer to our homeland.
If the Palestinian-Arabs wanted to take a big bite out of Israel in order to create a criminal-terrorist entity on Jewish land, we've certainly given them every opportunity, but they always refuse.
"Palestine," it must be understood, refers to a region, not a nation. Just as "Saharan" is not an ethnicity and "Californian" is not an ethnicity, so "Palestinian" is not an ethnicity, either. Everyone who lives in California, is a "Californian." That is it and that is all. If you are resident of the state of California then, whatever else you may be, you are very definitely a Californian.
The same is true for everyone who lives in the Land of Israel. They are all "Palestinian" in the sense that they all live in what was the British Mandate of Palestine, including the people of Jordan.
A "Palestinian" might be an Arab and he or she might be a Muslim, but there are all sorts of "Palestinians" who are not Arab. The Palestinian Authority is willing to accept the idea of an "Arab" Christian as "Palestinian," but that is where the door shuts closed. All others, despite residing in the region for perhaps generations, can never be considered "Palestinian" in the hard-right racist manner that the PA determines such things.
At the end of the day, however, everyone who lives in Eretz Israel is a "Palestinian," if we need to even use such terminology. There are Arab-Palestinians and Jewish-Palestinians and Rosicrucian-Palestinians and, presumably even, Chinese-Buddhist-Palestinians.
The Arabs may represent a significant portion of what was once the British Mandate of Palestine, but they never represented all of it. The Jews were always willing to share, just as the Arabs were always determined to prevail in a zero-sum contest against their formerly persecuted subjects.
But if one is an all-or-nothing kind of person and if you cannot grab it all, you very often get nothing.