There is a fascinating piece brought in the Shu"t HaRashbash (Rav Shlomo ben Shimon Duran) in siman 291 (although written clearly here) where it relates the following story:
Rabbeinu Yonah’s daughter was married to Ramban’s son, Shlomo. When Rabbeinu Yonah died, his daughter was pregnant and later gave birth to a boy. Since the custom amongst Sephardim is to name a grandson after his paternal grandfather, even when the grandfather is alive, the baby should have been named Moshe, the first name of Ramban. Ramban, however, advised naming the child Yonah after the maternal grandfather, Rabbeinu Yonah. The explanation he gave for his advice was based on the posuk brought in the Gemara Kiddushin 72b וְזָרַח הַשֶּׁמֶשׁ וּבָא הַשָּׁמֶשׁ – The sun rises and the sun sets, meaning before the light of one great scholar is extinguished the light of another great scholar begins to rise. This concept was in fact fulfilled, concludes Rashbash, and the baby Yonah grew up to be a great rabbi for the Jewish People:
וכן היה דנפק מיניה גברא רבה והיה רב וגדול בישראל
And so it was, he became a great man and was a big Rav amongst Israel.
Is it recorded anywhere who this Rav Yonah the grandson of Rabbeinu Yonah and Ramban is?
