As a followup to a previous post, here is an excerpt from the obituary for R. Yosef Tzvi Dunner, zt”l, that appeared in Dei’ah veDibur:

At the age of 19 he wanted to leave home to study in one of the illustrious yeshivas of Lithuania, but his father felt that given the dearth of rabbonim in Germany communities, before going to yeshiva he should study at a place that provides rabbinical training (smichus). He sent the young man to Beis Hamedrash Lerabbonim in Berlin, which was headed by HaRav Yechiel Yaakov Weinberg, the author of Seridei Eish. There he continued his intensive learning day and night, amassing tremendous knowledge of Shas and poskim.