was introduced to Vietnamese. As for syntax and vocabulary this Sino-Vietnamese language was no more different from the Chinese of Beijing than medieval English Latin was different from the Latin of Rome. Its major influence comes from Vietnamese Literary Chinese (Chữ Hán). The term Chữ Nôm (𡨸喃 "Southern characters") refers to the former transcription system for vernacular Vietnamese-language texts, written using a mixture of original Chinese characters and locally coined Nôm characters not found in Chinese to phonetically represent local Vietnamese words, meanings and their sound. However the character set for chữ Nôm is extensive, containing up to 37,000 characters, and many are both arbitrary in composition and inconsistent in pronunciation. Hán Nôm (漢喃 "Hán and chữ Nôm characters") may mean both Hán and Nôm taken together as in the research remit of Hanoi's Hán-Nôm Institute, or refer to texts which are written in a mixture of Hán and Nôm, or some Hán texts with parallel Nôm translations. There is a significant orthographic overlap between Hán and Nôm and many characters are used in both Hán and Nôm with the same reading. It may be simplest to think of Nôm as the Vietnamese extension of Han characters. The term Chữ Quốc ngữ ("national language script" or 𡨸國語) means Vietnamese in the romanized or transliteration script. History Chữ Hán Chinese characters are specifically called (), () or (, ) in Vietnamese. or is commonly used to describe Mandarin Chinese, as well as for Chinese in general. Possibly even a thousand years earlier, in the late first millennium BC, Yuè elites in what is now southern China may have already adopted a form of writing based on Chinese characters to record terms from their own languages. During the Chinese rule from 111 BC to 905 AD, Chinese characters had been used as the official writing of the region. Local texts written in Chinese probably also included some characters adapted to represent Proto-Viet-Mường sounds, usually personal names or Vietic toponyms that had no Chinese equivalent. According to some scholars, the adoption or had been started by Shi Xie (137–226), but many disagree. The first wholly vernacular Vietnamese writing transcribed in Chinese characters started in late-Tang period, around ninth century by . These writings were at first indistinguishable from contemporaneous classical Chinese works produced in China, Korea or Japan. These include the first poems in Literary Chinese by the monk (), the (), and