To the Editor—Since human life began, epidemics have been a threat to human health. ^{Reference Jones1} Today, coronavirus disease 2019 (COVID-19) has spread almost all over the entire world, and apparently one of the most important ways to prevent the transmission of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) is by wearing a face mask. ^{Reference Bundgaard, Bundgaard, Raaschou-Pedersen, von Buchwald, Todsen and Norsk2} A face mask largely prevents the transfer of airborne particles to the human respiratory system and can therefore play a significant role in preventing the spread respiratory viruses during epidemics. ^{Reference Loeb, Dafoe and Mahony3,4}

Interestingly, the mask has been used since ancient times in Iran; however, it should not be confused with the clothing used for women’s face veil. The word equivalent to the mask in ancient and medieval Iran was panam or pandam, which is also mentioned in the Avesta, ^{Reference Speigel5} the holy book of Zoroastrians, in the religious rituals of the followers of the ancient prophet of Iran. ^{Reference Boyce6} The Iranian word panam is used in most middle and modern Iranian languages and dialects. This word in the Avestan language means holder and keeper against something, and the Pahlavi Persian language includes the words padam, pandam, and phanom.

According to Pahlavi texts, the panam, now called the veil by Iranian Zoroastrians, refers to 2 pieces of white cotton cloth that are hung over the mouth and tied with 2 ribbons at the back. This small cotton curtain, which according to the Pahlavi interpretation of the description in the Avesta, should be 2 inches below the mouth and should be used when the priest performs a religious ceremony in front of the sacred fir. In fact, the use of panam was to prevent the breath and steam of the mouth, which was considered polluted, from reaching the sacred element of fire. Therefore, it was a religious device of priests. ^{Reference Boyce6}

Also, ancient Iranians who were honored by the king had wear a panam in front of their mouths to show respect for the king. Ancient Iranian physicians, after observing and treating a patient with an infectious disease, did not immediately treat another patient; first, they cleaned themselves as much as possible to prevent transmission of the disease. During treatment, they wore a scarf or cloth to prevent contamination. The cloth, which covered the face from the protrusion of the nose to under the chin and fastened with strings at the back of the head, seems to be very similar to today’s surgical masks (Fig. 1). ^{Reference Elgood7,Reference Elgood8}

Fig. 1. Schematic representation of face mask by Iranian Zoroastrians.

The constant medical use of panam is also recorded throuhgout the Middle Ages. One of the most famous physicians of the 15th century, Baha al-Dawla Razi, recommended that people wrap a piece of cloth around their airways and soak it in vinegar, onion, and garlic to prevent the spread of diseases (Fig. 2). ^{Reference Kholasat al-Tajarob9} This recommendation seems to be the most significant medical advice to prevent respiratory diseases in Iranian medicine. ^{Reference Elgood8,Reference Elgood10}

Fig. 2. Mask use instructions in the 15 th century suggested by Baha al - Dawla Razi (http://172.17.20.22:8888/site/catalogue/491189).