Rabbi Shimshon of Ostropola was a Kabbalist, that was killed during the Chmelnitzki Massacres in 1648-9.
Rabbi Shimshon of Ostropola was a Kabbalist, born in Koretz in 1600 to his father Reb Pesach, son-in-law of Reb Shamshon, son of Reb Betzalel Liva, brother of the Maharal of Prague.
Rabbi Natan Neta Hanover, a survivor of the Decrees of Tach ve'Tat (5408-5409; 1648-1649; the Chmelnitzki Massacres) when 100,000 Jews in Poland were massacred; writes in his book Yavan Metzulah:
"During the period of the Decrees of Tach ve'Tat, There was among them a wise man, a kabbalist, a man of God, and his name was Rabbi Shimshon from Ostropalia. An angel (Maggid) came to him every day and studied Torah secrets with him, and he wrote a commentary on the Zohar according to the Kabbalah of The Ari, but we did not merit to see this commentary in print. And this Maggid warned before the decrees that the people need to do great repentance in order to cancel the great calamity which was about to befall them. And so they did, they repented in all the communities, but it was already too late, the decrees were signed. When the enemies (the Cossacks) came and surrounded the city, Rabbi Shimshon and 300 great wise people entered the Synagogue wearing talits and shrouds. They prayed until they were all killed by the enemies."
The Ramchal writes in his Sefer Eitz Chaim that Rabbi Shamshon besworn the Sitra Achra regarding the Decrees of Tach ve'Tat, which answered that only if the Shabbat, Milah, and the Torah should be abolished will the decrees be abolished. Rabbi Shamshon answered that not even ONE letter in the Torah should be abolished. What Ramachal writes is seen as a parallel to the times of Rebbi Akiva, at which time was also a time of Kiddush Hashem in the face of the government (Roman government) decreeing against the Torah, Shabbat, and Milah.
Rabbi Shamshon wrote a commentary to Sefer HaKarnayim, called Dan Yadin (published in Zolkiev in 1709). Sefer HaKarnayim is an abstruse kabbalistic writing by Rabbi Yitzchak (son of the RABAD). Some say Sefer HaKarnayim was written by Rabbi Aharon of Kardina. Rabbi Shamshon's commentary on the Zohar called Machaneh Dan had not been printed yet. The famous Rabbi Tzvi Elimelech of Dinov (Bnei Yisaschar) offered his entire library of holy books to anyone who would find him a manuscript copy of this book. Someone did find one, but he arrived shortly after R' Tzvi Elimelech's death. Rabbi Shimshon used the name Dan for his writings because he believed his soul's origin was from Dan, son of Yaacov Avinu (Jacob). (To note that Shimshon Hagibor (his namesake) was of Shevet Dan).
Rabbi Shimshon's most famous writing is his kabbalistic composition related to Passover (on the 10 Makkot), which promises its readers protection for the entire year if read on the night of the Seder. It appears in some Pesach Haggadot.
Also well known is his writing regarding the 42 Masoyois (places of rest from Egypt to the Promised Land), also regarded as a Segulah.
The secrets of Kabbalah were very sacred in the eyes of Rabbi Shimshon, and he was afraid to reveal them. In his writings, he often asks God for forgiveness in case he reveals something he was not supposed to.
Some of his Torah discourses and thoughts were recorded in the book Nitzotzei Shimshon (Hebrew).
May the merit of the tzaddik Rabbi Shimshon of Ostropola protect us all, Amen.
Among his famous descendants are Rabbi Yaakov Yosef of Polnoye (pupil of the Baal Shem Tov), Rabbi Liber (the elder) of Barditchev, and Rabbi Meshulam Deivish Heller of Zbarish.