Çavuş, also anglicized Chaush and Chiaus (from Turkish: çavuş, "messenger") was an Ottoman title used for two separate soldier professions, both acting as messengers although differing in levels. It was a rank below agha and kethüda in units such as the Janissaries and Sipahi, and was also a term for members of the specialized unit of çavuşān (also çavuşiyye,çavuş(an)-i divan(i)) consisting of combined cavalry and infantry serving the Imperial Council (as in Ottoman Egypt). The leaders of the council's çavuş were titled çavuşbaşı (or başçavuş). The çavuşbaşı was an assistant (or deputy) to the Grand Vizier, dealing with security matters, accompanying ambassadors visiting the Grand Vizier, and also carried out the first examination of petitions submitted to the Council, and led council meetings when the Grand Vizier was not present. The title has its origin in Uyghur use, where it was the title of ambassadors, and then entered Seljuq use for Byzantine imperial messengers, and Persian and Arabic use for various court attendants.