Rabbonim in Ashkenaz

In this posting there will be place for inquiries and data about the Rabbonim in Ashkenaz.

Rav Hamburger told me the following:
Rav Yonah Yosef Halevi Horowitz was the last Rov of KAJ FFAM, after Rav Shlomo Zalman Breuer. Rav Yosef Breuer was the Rosh Yeshiva of FFAM (instead of his father R' Shlomo Zalman), but was not the Rov of KAJ.
Later in the US Rav Yosef Breuer became the Rov of KAJ WH, but this is a different story.
You can find the basic biography of Rav Horowitz in the introduction to his book "חגוי הסלע" (which can be found also in Otzar Hachochma).

Michael