Rabbeinu Yosef Yona Tzvi Horowitz was born in Unsdorf (Huncovce, Slovakia) in 1892. Born into a rabbinical family, Rav Horowitz was given leadership positions in the family Yeshiva at a young age. At age 27, upon the passing of the Rosh Yeshiva Rav Shmuel Rosenburg, Rav Horowitz was appointed as his successor and tasked with leading a yeshiva composed of close to 400 students. Over the next few years, he steadily expanded the Yeshiva, and in 1923 published the work of his grandfather in a sefer titled Baer Shmuel. Rav Horowitz had a very broad personality and also involved himself with the greater community. In addition, he gained a deep understanding of many secular subjects and worldly topics. In 1926, the Rav of the Israelitische Religionsgesellschaft in Frankfurt, Rav Shlomo Zalman Breuer, passed away. This created much turmoil regarding who should succeed the rabbinate. Eventually Rav Horowitz was chosen due to his immense Torah knowledge, appreciation for academic development, and ability to bridge the Frankfurt community with the Jews of Eastern Europe. As can be imagined, accepting this position was not a simple matter since Rav Horowitz was already a great leader in Eastern Europe. However, upon presenting the issue to numerous Torah leaders, the unanimous position from a wide spectrum of Gedolim was that he should accept the position. In hindsight, this move was an incredible act of hashgacha, as he was the only citizen of Unsdorf to survive the Holocaust. The Horowitz family was not new to Frankfurt; Rav Horowitz was a descendant of Rav Pinchas Horowitz (author of Haflah), who also served as the Rav there. Rav Horowitz began his tenure right before Rosh Hashana of 1929, and for the next eleven years led the Frankfurt Kehillah. In 1940, Rav Horowitz fled to England, where he became a leader among the Jewish kehillos in London. After the war, Rav Horowitz moved to the United States and established the Yeshiva Baer Shmuel in Boro Park. After building the Yeshiva, Kollel, and other facilities, Rav Horowitz decided to move to Eretz Yisroel, and in 1965 left Brooklyn, and handed over the leadership of his institution to his son Rav Moshe Horowitz. Rav Yosef Yona Tzvi Horowitz passed away in 1970.