According to the Outeiro da Assenta archaeological remains, humans have settled in Óbidos since at least the Lower Paleolithic period. Several million years and evolutionary leaps later, a Celtiberian castro (settlement) emerged. It would eventually become an important trading post for Phoenicians and later an important Roman military outpost. After the Islamic period came Afonso Henrique's conquest of the town in the 12th century, followed by construction of the famous Óbidos Castle that is the local landmark. Ever since king Dom Dinis offered the town as a wedding gift for his wife Isabel, Óbidos belonged to the Portuguese queens, right up until the 19th century - this fact explains why so many architectural landmarks (such as the Aqueduct) were built. The 1755 earthquake and the Peninsular War in the early 19th century took their toll and led to renovations in the historic centre, but Óbidos has never lost its medieval town charm.