Modern Standard Hindi is based on the Delhi dialect, the vernacular of Delhi and the surrounding region, which came to replace earlier prestige dialects such as Awadhi, Maithili (sometimes regarded as separate from the Hindi dialect continuum) and Braj. Urdu – considered another form of Hindustani – acquired linguistic prestige in the latter part of the Mughal period (1800s), and underwent significant Persian influence. Modern Hindi and its literary tradition evolved towards the end of the 18th century. John Gilchrist was principally known for his study of the Hindustani language, which was adopted as the lingua franca of northern India (including what is now present-day Pakistan) by British colonists and indigenous people. He compiled and authored An English-Hindustani Dictionary, A Grammar of the Hindoostanee Language, The Oriental Linguist, and many more. His lexicon of Hindustani was published in the Perso-Arabic script, Nāgarī script, and in Roman transliteration. He is also known for his role in the foundation of University College London and for endowing the Gilchrist Educational Trust. In the late 19th century, a movement to further develop Hindi as a standardised form of Hindustani separate from Urdu took form. In 1881, Bihar accepted Hindi as its sole official language, replacing Urdu, and thus became the first state of India to adopt Hindi.