Ancient Jewish tradition identified this mysterious person called “Shiloh” in Genesis 49:10, as being the Messiah:

“Until Shiloh comes”: this alludes to the King Messiah” – Midrash Genesis Rabbah 98.8, ibid 99.9

“The Messiah’s name is Shiloh” – Midrash Lamentations Rabbah I.16.51

The Targums [Ancient Aramaic translations and paraphrases of the Hebrew Bible] are almost unanimous in giving “Shiloh” a Messianic interpretation for they rendered Genesis 49:10:

“Until the Messiah comes whose is the Kingdom” – Targum Onkelos

“Until the time King Messiah shall come, whose is the kingdom” – Targum Jerusalem

“Until the time King Messiah shall come whose is the kingship” – Targum Neofiti I

“Until King Messiah shall come, the youngest of his sons” – Targum Psalm Jonathan or Jerusalem I

There is great insight in the extensive Targumic and rabbinic tradition (see Rashi ad loc., Sanhedrin 98b B.T.; Midrash Genesis Rabbah 98.8; 99.8; Tanchumah Vayehi 10; Midrash haGadol I.735-739; Journal of Philology Vol. XIV [1885] pages4-22), that ascribes a Messianic interpretation to the verse: “The scepter shall not depart from Judah…until Shiloh comes and to him shall be the obedience of the peoples.” They knew that the ancestral right to kingly leadership, resting in the Davidic line of the tribe of Judah, would cease at the coming of the “Messiah, the son of David” (a common appellation of King Messiah found in rabbinic writings). For the Messiah was the culmination of the royal line originating from David, the first king of the tribe of Judah. And just as King David was “the youngest” (1 Samuel 16:11; 17:14) of Jesse’s sons, so the Messiah at the end of the line of David’s “sons” may be said to be “King Messiah…the youngest of his [King David’s] sons” – Genesis 49:10. Targum Psalm Jonathan or Jerusalem Targum I.

The scribes knew that what belonged to him (the King Messiah) “whose it is”, was the scepter, the kingdom and the obedience of the peoples. Furthermore they also knew that this mysterious personage was to have a very precious heritage in store for him at his coming, which is why the later redactors of the Septuagint rendered Genesis 49:10 in their revisions:

There are abundant writings from the ancient rabbis that the name “Shiloh”, which is an idiom for the Messiah. The word “Shiloh” was frequently used to describe the Messiah.

The world was created for the sake of the Messiah. What is this Messiah’s name? The school of Rabbi Shila said: His name is Shiloh, for it is written: until Shiloh comes. (Babylonian Talmud, Sanhedrin 98b, Rabbi Johanan)

The Targum Yerushalmi further states:

Kings shall not cease from the house of Judah – until the time of the coming of the King Messiah, to whom all the dominions of the earth shall be subservient. (The Search for the Messiah, Page 100, Dr. Mark Eastman)

All the three Targums interpret Shiloh of the Messiah. As many of the Jewish writers do, both ancient and modern {Zohar in Genesis fol. 32. 4. & in Exodus fol. 4. 1. & in Numb. fol. 101. 2. Bereshit Rabba, fol. 98. sect. 85. 3. Jarchi & Baal Hatturim, in loc. Nachmanidis Disputat. cum Paulo, page 53. Abarbinel. Mashmiah Jeshuah, fol. 10. 1. R. Abraham Seba, Tzeror Hammor, fol. 36. 4. & 62. 2}.

It also is the name of the Messiah in the Talmud { T. Bab. Sanhedrin, fol. 98. 2}, and in other writings {Echa Rabbati, fol. 50. 2}.

But there is much more about Genesis 49:10.

Read here: Judah – The Lawgiver of God (Hebrew: Mechoqeck)