Historians believe that Newars first settled the Kathmandu Valley in the early 3rd or 4th century. Kathmandu, Patan, and Bhaktapur were the capitals of autonomous Newar Kingdoms. Before the invasion of the present Shah Dynasty in 1768, almost all the people in the Kathmandu Valley were Newars. Kathmandu has experienced significant migrations from different parts of the country, as well as from neighbouring countries, but Patan and Bhaktapur are still largely Newar. The distinctively beautiful temples and palaces of the Kathmandu Valley are largely the product of Newar architects, artisans, and sculptors Indeed, Newar architects are responsible for the inventing pagoda architecture that is one of Asia's hallmarks.      Newars speak Newari, which is an independent language with its own script and a rich literature. It belongs to the Himalayan group of the Tibeto-Himalayan branch of the Tibeto-Burman sub family of language. The earliest stratum of the Newar population may have come from Tibet. The ancient Newars were predominantly Buddhist, but, with the political domination of Hindu rulers, new practices and beliefs have been introduced. Many Newars today practice a combination of Vajrayana Buddhism and Hinduism. The social structure of Newars is built on the caste system, and many Newars pursue occupations traditionally assigned to their castes, but the attitude towards caste is definitely changing      One remnant of the occupational caste system among modern Newars is the surnames of hierarchica, for example, Maharjan (farmers), Awale (brick makers), Shrestha (administrators), Rajkarnikar (confectioners), Vajracharya (Buddhist priests), Tamrakar (copper craftmen), Manandhar (oil pressers), Shakya (goldsmiths), Ranjitkar (dyers), Nakarmi (blacksmiths), Kulu (drum-makers), and Chami (sweepers).      Today Newars still find time for festivals and social ceremonies with great enthusiasm to continue their unmatched cultural heritage. Many rituals are related to the stages of life--birth, first rice-feeding, childhood, puberty, marriage, old age, and death. The complexity and all encompassing nature of these rituals cannot be exaggerated. For instance, Newar girls are married thrice in their lives. The first marriage is called "Ihi." This two-day ceremony takes place when the girl has reached an age of an odd number of years (5, 7, 9, etc.) before she starts menstruation. The second marriage is called "Bara Teyegu", This is marriage to the Sun. This takes place when a girl reaches menarche. Because menstruation is considered ritually impure, she undergoes ritual confinement for 12 days. The girl is separated from all males and from sunlight for 12 days while female relatives dote upon her. On the twelfth day she emerges and pays homage to the sun. The third marriage is, of course, the human conjugal relationship      Newars have five rituals, called Jungku Yagu, which are performed to honor a person between the age of 77 and 106. These are performed at: 77 years, 7 months, and 7 days; 84 years, 4 months, and 4 days; 88 years, 8 months, and 8 days; 99 years, 9 months, and 9 days; and finally, at 105 years, 8 months, and 8 days.