Regarding the laws of mezuza, Rav Yehuda quotes Shmuel as teaching that putting a mezuza on a stick so that it can be placed near the doorpost – or even tied on to it – is not a fulfillment of the mitzva, and, in fact, is dangerous. Nevertheless, the Gemara reports that the household of King Munbaz did this very thing when they stayed in inns while traveling, so that they would at least have the remembrance of the mitzva.
Rashi explains that since the mitzva was not fulfilled, in consequence the person does not receive the protection offered by the mezuza, and will find himself in danger. The family of King Munbaz was traveling, and, as such, was not obligated in the commandment – the Talmud Yerushalmi suggests that it was during wartime – and they wanted, nevertheless to remember the mitzva, yet have a convenient method of taking it with them.
Munbaz was the king of Adiabene at the end of the Second Temple period. Adiabene was a small kingdom in the north of Syria on the banks of the Euphrates. In the generation prior to the destruction of the second Temple, Queen Helene, together with her sons Munbaz and Izitus, began to study Torah with Jews who traveled through their kingdom, and eventually converted to Judaism. It appears that other members of the ruling elite did so, as well. Helene visited Jerusalem a number of times and made donations both to the Temple and to the destitute people living there. Her children followed in her footsteps, and even sent troops to support the Jewish uprising during the Great Revolt. Upon his mother’s death, Munbaz declined the position of monarch, allowing his brother to become king, but he took the throne upon his brother’s death. Stories about this family, including detailed accounts of their conversion, appear in Josephus. It appears that after his death, Munbaz was buried in the Tombs of the Kings in Jerusalem together with other members of his family.
The Talmud often comments that the activities of this family were praiseworthy, and we find a detailed description of their lives and their conversion to Judaism in the works of Josephus.