1205 BCE - Merneptah Stele
Based on archaeological findings, it does not appear that Israelites began as the Bible tells it (the seven Canaanite patriarchs and matriarchs, slavery in Egypt, and then conquering the land of modern-day Israel and parts of Jordan, Syria, and Lebanon.) Rather, the Israelites were probably Levantine people who already were living there, who developed a folk religion and shared tribal identity that became what we now think of as Israelite.
The Jews also perhaps originated as a people much more recently than Biblical records claim. "Rather than 2000-1800 BCE, the history of Israel seems to begin around 1200 BCE, when Canaanite peoples from the lowlands began to establish new settlements in the highlands, in what scholars now generally call the “pre-monarchical period”" (source). Though the people may have been a unified civilization before 1200 BCE, the oldest record of the people of "Israel" is the Merneptah Stele.
The Merneptah Stele was discovered in Thebes in Greece. The stele describes Pharaoh Merneptah’s military victories in 1207 BCE, including Israel. "Israel, then, must have been a people strong enough for Merneptah to mention them in boasting of his victory. If Israel was some small nomadic tribe just beginning to settle in Canaan, Merneptah wouldn’t have had anything to boast about."
The Etrog Incident
The etrog originated in the Yunnan province of China, and spread through northern India as a part of Ayurvedic medicine. When Darius I conquered India for the Persian Empire in 516 BCE, the etrog spread to the Middle East and Mediterranean. While a common variant in China is the Buddha's Hand etrog (see below), the more common variant Jews use today comes from Diamante in Calabria, Italy. Yemenite Jews have also bred a strain of giant etrog (see below)!
The etrog only became a major symbol for Israelites during the Second Temple period (539 BCE-70 CE), during which depictions of the etrog appeared on coins and in mosaics. For example, look at these coins from the 1st Jewish War (69-70 CE) and the Bar Kochba Revolt (134-135 CE), and at this mosaic in the Hammat Tiberius Synagogue (c. 250 CE).
We also hear in Josephus's historical writings about an early case of an etrog a little after 100 BCE, which I call "the etrog incident": the Hasmonean (Hellenistic Greek) king of Judea, Alexander Yanai (perhaps better known as the husband of Queen Salome) intentionally desecrated the Temple altar while performing the High Priest's duties in order to show his displeasure with the Pharisees (the proto-rabbis). The crowd pelted Alexander Yanai with etrogim and said nasty things about his mother. Outraged, Alexander Yanai killed 6,000 people and crucified several rabbis, triggering a Judean civil war.
The Mishnah corroborates with this incident, though it doesn't say who it was:
(ט) נִסּוּךְ הַמַּיִם כֵּיצַד. צְלוֹחִית שֶׁל זָהָב מַחֲזֶקֶת שְׁלשֶׁת לֻגִּים הָיָה מְמַלֵּא מִן הַשִּׁלּוֹחַ. הִגִּיעוּ לְשַׁעַר הַמַּיִם, תָּקְעוּ וְהֵרִיעוּ וְתָקָעוּ. עָלָה בַכֶּבֶשׁ וּפָנָה לִשְׂמֹאלוֹ, שְׁנֵי סְפָלִים שֶׁל כֶּסֶף הָיוּ שָׁם. רַבִּי יְהוּדָה אוֹמֵר, שֶׁל סִיד הָיוּ, אֶלָּא שֶׁהָיוּ מֻשְׁחָרִין פְּנֵיהֶם מִפְּנֵי הַיָּיִן. וּמְנֻקָּבִין כְּמִין שְׁנֵי חֳטָמִין דַּקִּין, אֶחָד מְעֻבֶּה וְאֶחָד דַּק, כְּדֵי שֶׁיְּהוּ שְׁנֵיהֶם כָּלִין בְּבַת אַחַת. מַעֲרָבִי שֶׁל מַיִם, מִזְרָחִי שֶׁל יָיִן. עֵרָה שֶׁל מַיִם לְתוֹךְ שֶׁל יַיִן, וְשֶׁל יַיִן לְתוֹךְ שֶׁל מַיִם, יָצָא. רַבִּי יְהוּדָה אוֹמֵר, בְּלֹג הָיָה מְנַסֵּךְ כָּל שְׁמֹנָה. וְלַמְנַסֵּךְ אוֹמְרִים לוֹ, הַגְבַּהּ יָדֶךָ, שֶׁפַּעַם אַחַת נִסֵּךְ אֶחָד עַל גַּבֵּי רַגְלָיו, וּרְגָמוּהוּ כָל הָעָם בְּאֶתְרוֹגֵיהֶן:
(9) With regard to the rite of water libation performed in the Temple during the Festival, how was it performed? One would fill a golden jug with a capacity of three log with water from the Siloam pool. When those who went to bring the water reached the Gate of the Water, so called because the water for the libation was brought through this gate leading to the Temple courtyard, they sounded a tekia, sounded a terua, and sounded another tekia as an expression of joy. The priest ascended the ramp of the altar and turned to his left. There were two silver basins there into which he poured the water. Rabbi Yehuda said: They were limestone basins, but they would blacken due to the wine and therefore looked like silver. The two basins were perforated at the bottom with two thin perforated nose-like protrusions. One of the basins, used for the wine libation, had a perforation that was broad, and one, used for the water libation, had a perforation that was thin, so that the flow of both the water and the wine, which do not have the same viscosity, would conclude simultaneously. The basin to the west of the altar was for water, and the basin to the east of the altar was for wine. However, if one poured the contents of the basin of water into the basin of wine, or the contents of the basin of wine into the basin of water, he fulfilled his obligation, as failure to pour the libation from the prescribed location does not disqualify the libation after the fact. Rabbi Yehuda says: The basin for the water libation was not that large; rather, one would pour the water with a vessel that had a capacity of one log on all eight days of the Festival and not only seven. And the appointee says to the one pouring the water into the silver basin: Raise your hand, so that his actions would be visible, as one time a Sadducee priest intentionally poured the water on his feet, as the Sadducees did not accept the oral tradition requiring water libation, and in their rage all the people pelted him with their etrogim.
(יד) שפעם אחת נסך. צדוקי אחד את המים על רגליו:
(14) שפעם אחת נסך – one Sadducee [offered a libation] with the water on his feet.