Nepal's history dates back to ancient times, with the earliest evidence of human settlement found in the Kathmandu Valley. The region was influenced by various cultures, including the Malla kings in the medieval period, who contributed to art and architecture. In the 18th century, Prithvi Narayan Shah unified several small kingdoms to form modern Nepal. During the 19th century, Nepal faced conflicts with the British Empire, leading to the Anglo-Nepalese War. The Treaty of Sugauli in 1815 established Nepal's borders. In the 20th century, political changes occurred, including the end of the monarchy in 2008, transitioning Nepal into a federal democratic republic.