The Central and Western Himalayas have historically been characterized by a variety of small and medium-sized political units rather than by large, centralized empires. The difficult terrain, deep valleys, high mountain ranges and relative isolation of settlements encouraged the emergence of localized kingdoms, principalities and tribal polities. At the same time, these regions were connected with the plains of northern India through important trade routes, pilgrimage networks and military movements. Consequently, the political history of the Himalayas reflects both regional autonomy and interaction with larger states of the Indian subcontinent. In the Western Himalayas, the region of Kashmir developed one of the most important political formations. Kashmir possessed a fertile valley surrounded by mountains, which provided favourable conditions for the growth of a relatively centralized kingdom. The Kashmir Valley became a major centre of political power, culture and learning. Several dynasties ruled Kashmir at different times, including the Karkotas, Utpala and Lohara dynasties. The Karkota rulers, particularly Lalitaditya Muktapida, expanded the political influence of Kashmir considerably. Kashmir maintained relations, sometimes friendly and sometimes hostile, with neighbouring regions of the Punjab, Tibet and Central Asia. Its geographical position made it strategically important and brought it into contact with wider political developments. Other important polities developed in the hill regions adjoining Kashmir. The areas of Jammu, Himachal Pradesh and the western Himalayan valleys contained numerous small kingdoms and chiefdoms. These included the kingdoms of Chamba, Kangra, Kullu, Mandi and Suket. Their political organization was generally based on hereditary kingship, with rulers exercising authority over particular valleys and surrounding mountain territories. The difficult geography prevented the easy establishment of extensive centralized administration. As a result, political authority was