Farsi (Persian) is the official language of Iran. More than half of Iran’s population are Persian speakers. According to the Iran Chamber Society, Classical Persian, which was also infused with Arabic words, “remained essentially unchanged until the nineteenth century”. This was until a dialect, Teheran (or Tehrani), rose to prominence after the Qajar Dynasty chose Tehran as its capital, moving the centre from Shiraz. The dialect became the basis of Contemporary Standard Persian.