Reykjavík is believed to be the location of the first permanent settlement in Iceland, which, according to Landnámabók, was established by Ingólfr Arnarson in AD 874. Until the 19th century, there was no urban planning in the city location. The city was founded in 1785 as an official trading town and grew steadily over the following decades, as it transformed into a regional and later national centre of commerce, population, and governmental activities. It is among the cleanest, greenest, and safest cities in the world.