Nepalese art is religious art. Its main purpose is not aesthetic but inspiring. The image is a means to the realization of a certain state of consciousness and is not intended to be a representation of reality or a pleasurable decoration. 
Through two examples from the probably oldest temple in Nepal, the Changu Narayan Temple, and Temple District, this statement of a former renowned professor of Nepalese art and religion, Prof. Lydia Aran, shall be presented and combined with personal impressions.
During the Malla Dynasty (1201 - 1779) favorable economic, political, and social conditions brought architecture, sculpture, painting, and metalwork (copper and brass), as well as urban planning and literature to a great height. At that time, Nepal was identical with the Kathmandu valley, which developed into a valley richly decorated with temples and shrines. Already since the 5th century (or some centuries earlier, as some authors assume ) there are reports and archeological evidence about the highly developed art in the Kathmandu valley. One of the oldest temple districts in the valley is Changu Narayan, dedicated to the divine principle of Vishnu. Together with Brahma and Shiva, Vishnu forms the Hindu trinity. Vishnu is regarded as the builder and sustainer of the universe and is worshipped as the sun god. The temple district of Changu Narayan is situated on a hill near the city of Bhaktapur, which means the city of devotees.
The main temple is a two-story pagoda. It has a long history of construction, destruction, fires, rebuilding, and renovation. The temple was already mentioned in an inscription in the temple courtyard from the year 464, with the remark that the temple was renewed and extended in this year.  From this, it can be concluded that Changu Narayan was already built in the 1st or 2nd century. The temple district is mythologically closely connected with the origin and history of the Kathmandu valley.  The temple itself is surrounded by different buildings, resulting in a square courtyard, various sculptures, smaller temples, and shrines, reflecting the long history of the temple. After entering through the eastern gate, the visitor finds himself in another world, a world of peace and serenity, overwhelmed by the beauty of the temple and the different shrines. The complex was severely damaged during the earthquake in 2015 but is now slowly being rebuilt. The serenity is still clearly noticeable despite the present bustling pace of reconstruction.
A description of the temple and its mythological significance in the creation of the Kathmandu Valley goes far beyond the scope of this article. I will only discuss the significance of two sculptures, those of the incarnations of Vishnu in the form of Vamana and Krishna and the stories associated with them. 
Vishnu Trivikranta, Vishnu with the three steps, Changu Narayan, Nepal
The sculpture with the name Vishnu Trivikranta, (Vishnu with three steps) is attributed to Vishnu’s incarnation, called Vamana, his 4th incarnation. The original statue from the year 464 is kept in the National Art Museum. A copy (from the 8th century!) is located in the temple district, Changu Narayan. This sculpture is easily overlooked, as it is not taller than about 80 cm, built into an inconspicuous brick frame that is supposed to protect it from theft and destruction. The religious and mystical meaning of the sculpture is still alive today, as the daily sacrifices of the believers show.
How the demons were banished
The finely chiseled relief shows Vishnu (in the form of Vamana), how he spans the whole world with one step. Below the big step, our world is presented, above the step is the world of the gods. To this sculpture, the following story is told: The king of demons, Boni, had extended his power so far that he ruled our entire world. One day he felt strong enough that he tried to bring also the world of gods under his rule. The gods became worried and went to Vishnu, the preserver of the world and the universe, asking for help. Vishnu promised to dissuade Boni from his plan. He took the form of a dwarf (Vamana) and went to him. Submissively he asked for a favor. Boni, the great ruler of the world, promised the dwarf the fulfillment of his wish. The dwarf asked him to give him a piece of land that he could encircle with three of his steps. Boni laughed at this simple-minded request and granted it. As soon as the request was granted to Vishnu in the shape of the dwarf, he regained his divine form. He grew and grew so that with the first step, he spanned the whole world. In the second, he included the entire world of gods. Vishnu then pushed with the third step the demon king Boni into the underworld. With this, Vishnu freed our world and protected the dwellings of the gods from the attack of the demons. Thereby, the world became peaceful and happy again, and also, the world of gods returned to its harmony.
Without knowing this story, I was attracted by the inconspicuous brick frame, and the sculpture walled into it during my first visit. Vishnu, the preserver of the world, spans the whole visible and invisible universe with one step, from the depth of the transient world up to the world of gods. Does this sculpture show us the way to overcome this world of limitations and contrasts, which we so often seek? When I was told the story of the demon king, I involuntarily had to think of the Old Testament and the battle between Lucifer and the archangel Michael (Isaiah 14:12-14). Could this sculpture not be an indication of the overcoming of separation and death of this world? In Hinduism, Vishnu is always present as a helper and as a conqueror of the transient world! In this figure, Vishnu swings his magical attributes (discus, conch shell, lotus blossom, and a club) high above himself as a sign of victory over the demons. The figure thus radiates comfort, security, and joy. The change from a dwarf to the sustainer of the physical and spiritual world wants to suggest that every human being is a dwarf, but one who, through and in Vishnu, can overcome the demons in himself and in the world.
Even today, many Nepalese and Indians pray to Vishnu when they see themselves persecuted by misfortune and strokes of fate. They ask him to send the demons, that could be behind these events, into the underworld, and thus save them from further misfortune.
(to be continued in Part 2)
 Lydia Aran: Art and Religion in Nepal; http://users.skynet.be/ragini_art/Symbolic_essay/art_and_religion_in_nepal.htm
 Malla dynasty: https://en.wikipedia.org/wiki/Malla_(Kathmandu_Valley)
 Jeff Lidke: Vishvarupa Mandir, A study of Changu Narayan, Nepal’s most ancient temple; Nirala Publications, New Delhi, 1996
 Ibid., pp. 87-88
 Ibid., pp. 51–62
 Hinduism knows of 10 incarnations of Vishnu. These incarnations take place always at the beginning of a new cosmic period (Yuga). Among the incarnations are Rama, Krishna, and Gautama Buddha. The 10. or last embodiment of Vishna, called Kalki, is still to come. (see also Ibid., pp. 114 -124)