A Prophet, who on the timeline of Jewish History, prophesied in the time of King Yoshiahu, who ruled over the Kingdom of Yehudah from approximately 640 B.C.E. - 610 B.C.E., during the fleeting reign of Yehoachaz (three months), during the eleven year reign of Yehoyakim, the very brief reign of Yehoyachin (also three months) and during the eleven years of the reign of King Tzidkiyahu, the last King of Yehudah, who was captured and blinded by the Babylonians, the People who destroyed and burned the Temple
and the City of Jerusalem in approximately 586 B.C.E.
What were his Main Prophecies?
He decried the prevalent idol-worship, the desertion of Hashem and His Torah by the Priests and Prophets of Israel, the terrible social injustice and corruption and widely practiced sexual immorality.
He was the Prophet who delivered the final warning to the People of the imminent national catastrophe of the destruction of the Temple and the capital city, Yerushalayim.
Some Midrashim on Yirmiyahu HaNavi:
" 'Cursed be the day that I was born' (Yirmiyahu 20:14) - the Ninth of Av (date of destruction of the Temple), when I was born." (Midrash Iyov Vertheimer)
"Yirmiyahu said, 'Master of the Universe, what sins have I done that in the days of all the Prophets who preceded me and those who will follow me, you did not destroy Your House, but only through me?' He answered, 'Even before I created the world, you were prepared for this mission." (Pesikta Rabati 27:5)
A Midrash on Yeshayahu and Yirmiyahu
All the harsh prophecies which Yirmiyahu would prophecy against Israel, Yeshayahu preceded and provided the healing. (Eichah Rabati 1:23)