The Exilarch ("Reish Galuta") of Babylonian Jewry, Huna Mori bar Mar Zutra, was executed in Pumpadita by order of the Persian emperor on the 18th of Tevet of the year 4229 from creation (469 of the common era). Also killed on that day was Rav Mesharshia bar Pekod (the third Jewish leader who was arrested with them, Rav Ameimar bar Mar Yenuka, was executed two months later).

The 18th of Tevet the yahrtzeit (anniversary of the passing) of Rabbi Zvi Elimelech Shapiro of Dynov (1783?-1841), author of the Chassidic work B'nei Yissachar.

Links: A story and a teaching