R. Ya’akov Emden’s son, R. Meir Constantiner had a suspicion that the Besht is part of the Shabetai Zevi sect, God forbid. However, he wanted to be fully convinced of this. So he traveled to the Besht. He was so impressed with the Besht’s conduct, that he became one of his first Chasidim.

I.F.

Sanzer Rebbe 

Rabbi Rotenberg