Why do the doctor in assassins creed 2 were masks

if you want to get technical, the doctors of those days wore beak shaped masks with a small breathing hole on the tip. they used to stuff the beaks with a sort of popourie of dried flowers for they beleived that the sweet smell of flowers would ward off the plague. the masks that those doctors wore are considered to be the earliest type of gasmask, save for people covering their mouths with cloth. not only did they put dried flowers into their masks, but also in the lining of their coats for the same purpose of warding off disease