The name "Colombo", first introduced by the Portuguese in 1505, is believed to be derived from the classical Sinhalese name Kolon thota, meaning "port on the river Kelani". Another belief is that the name is derived from the Sinhalese name Kola-amba-thotawhich means "Harbour with leafy mango trees" The author of the oldest Sinhalese grammar, Sidatsangarava, written in the 13th century wrote about a category of words that exclusively belonged to early Sinhalese. It lists naramba (to see) andkolamba (ford or harbour) as belonging to an indigenous source. Kolamba may also be the source of the name of the commercial capital Colombo.
As Colombo possesses a natural harbor, it was known to Indian, Greeks, Persians, Romans, Arabs, and Chinese traders over 2,000 years ago. Traveller Ibn Batuta who visited the island in the 14th century, referred to it as Kalanpu. Arabs, whose prime interests were trade, began to settle in Colombo around the 8th century AD mostly because the port helped their business by the way of controlling much of the trade between the Sinhalese kingdoms and the outside world. Their descendants now comprise the local Sri Lankan Moor community.