The plague was one of the oldest illnesses known to Iranian physicians. For instance, Abu Sahl Massihi (a Persian Christian physician in the 10th century CE) wrote a treatise on the plague (Maghaleh fi Tauon) and Ali Ibn Abbas Majusi Ahvazi (10th century CE) also known as Haly Abbas in the West described it in his medica book; Ibn-Sina or Avicenna the renowned Iranian physician pointed out the clinical presentation of the bubonic plague. several outbreaks of the human plague occurred during the Safavid period (1495 -1735 )In Ghazvin and Ardabil, around 30,000 people died. Another outbreak occurred in Qom, which continued for five years with 12,000 mortalities. During Shah Abbas reign (1587 -1628 ), the cholera and plague epidemics occurred concurrently and in Shah Safis reign (1628 -1642 ), an outbreak of severe plague occurred again in Ghazvin and spread to other cities. In Ghazvin 20,000 people died. After the collapse of the Safavid Dynasty and Irans occupation by the Afghan invaders, another plague outbreak occurred in Gilan Province in 1727 with a high mortality rate. Again it reoccurred in 1731 and around 20,000 expired in Hamadan and western Iran. Several villages were abandoned after an epidemic which killed up to 90% of the population.