Sattriya (Assamese: সত্ৰীয়া), or Sattriya Nritya, is a major Indian classical dance. This dance was initially created as part of Bhaona which are performances of Ankiya Nat, one-act plays, originally created by Sankardev, the 15th-16th century polymath from Assam. These dances are part of the living traditions today of Sattras, which are communities of live-in devotees belonging to the Ekasarana dharma, the religion established by Sankardev.
The themes played are related to Lord Krishna, sometimes other Vishnu avatars such as Rama and Sita  and stories from the epics (Mahabharata and Ramayana) are also referred to. The philosophic religion of Mahapurush Srimanta Sankaradeva was based on Vedanta, Bhagavadgītā and the Bhāgavata Purāna, so there is no presence of Radha in Sattriya dance presentations.
On November 15 in the year 2000, the Sangeet Natak Akademi of India recognized Sattriya as one of the eight classical dances of India. Modern Sattriya explores many themes and plays, and its performances are staged worldwide.
Sattriya is a classical dance of India, tracing its roots to ancient drama and music texts of India, particularly Bharata Muni's Nātya Śāstra. Its first complete compilation is dated to between 200 BCE and 200 CE, but estimates vary between 500 BCE and 500 CE. The most studied version of the Nātya Śāstra text consists of about 6000 verses structured into 36 chapters. The text describes the theory of Tāṇḍava dance (Shiva), the theory of rasa, of bhāva, expression, gestures, acting techniques, basic steps, standing postures – all of which are part of Indian classical dances.
 Dance and performance arts, states this ancient text, are a form of expression of spiritual ideas, virtues, and the essence of scriptures.
The history of dance arts in Assam goes back to antiquity, as evidenced by copper plate inscriptions and sculpture relating to Shaivism and Shaktism traditions. Singing and musical traditions, similarly, have been traced to Assamese chorus singing tradition for the Hindu epics: the Ramayana and the Mahabharata.
The modern form of Sattriya is attributed to the 15th century Sankaradeva, who systematized the dance using the ancient texts, and introduced drama and expressive dancing (nritta and nritya) as a form of a community religious art for emotional devotion to Krishna.
Since the 15th century, the Sattriya art grew as part of the Vaishnava bhakti movement, in Hindu monasteries called Sattra. The art was developed and practiced by monks in the form dance-dramas about legends and mythologies of Krishna, particularly from texts such as the Bhāgavata Purāna. One distinctive part of the Sattriya dance inside temples and monasteries is that the dance is not celebrated before any idol, but is performed before a copy of the Bhagavata Purana placed in eastern (sun rise) corner called Manikut of the dance hall (namghar).
These dance-dramas were, in the early days, written and directed by the Assamese poet-saint Sankaradeva, and by his principal disciple Madhavadeva. They were mostly composed during the 16th century. Once the domain of male monks, it is now performed by male as well as female dancers. In the second half of the 20th century, Sattriya Nritya moved from the sanctum of Assam's sattras / monasteries to the metropolitan stage.
The Sangeet Natak Akademi recognized Sattriya Nritya as an official classical dance of India in 2000. Sattriyas are now performed on world's stages.
Like the other schools of Indian Classical dance, Sattriya encompasses the principles required of a classical dance form: the treatises of dance and dramaturgy, like Nātya Śāstra, Abhinaya Darpana, and Śārngadeva's Sangīta Ratnākara; The Sangīta Ratnākara of Śārngadeva complements his Bhakti Ratnakara, which traces the Upanishads, Bhagavad Gita, Yoga and Vedanta themes, the ethical values such as non-violence (ahimsa), truthfulness (satya) and others, thus premising a theological foundation to Sattriya. To Shankaradeva, religious values, ethics, joys of life and performance arts were intimately linked, and he asked the leaders of Hindu monasteries to compose at least one play, during their tenure, before they die.
Sattriya repertoire (mārg) includes nritta (pure dance, solo), nritya (expressive dance, solo), and nātya (dramatic play, group). Like all major classical Indian dance forms, those three categories of performances are:
The hand gestures (mudras), footwork (padas), postures, rhythms, training of artistes and other aspects of the Sattriya dance drama closely follow those described in Nātya Śāstra and other classical Hindu dance texts, and are quite similar to other major classical dances such as Odishi, Kathakali, Bharatanātyam and others found in southern and northern India. Some basic elements and features of Sattriya match those found in the Manipuri dance found in neighboring Manipur state.
Sattriya Nritya is a genre of dance drama that tells mythical and religious stories through hand and face expressions. The basic dance unit and exercise of a Sattriya is called a Mati Akhara, equal 64 just like in Natya Shastra, are the foundational sets dancers learn during their training. The Akharas are subdivided into Ora, Saata, Jhalak, Sitika, Pak, Jap, Lon and Khar. A performance integrates two styles, one masculine (Paurashik Bhangi, energetic and with jumps), and feminine (Stri Bhangi, Lasya or delicate).
Traditionally, Sattriya was performed only by bhokots (male monks) in monasteries as a part of their daily rituals or to mark special festivals. Today, in addition to this practice, Sattriya is also performed on stage by men and women who are not members of the sattras, on themes that go beyond the mythological.
The plays choreographed in a Sattriya are those found in Hindu texts such as the Bhāgavata Purāna, the Epics, and the compositions by Assamese scholars. 
The costume of Sattriya dance is primarily of two types: the male costume comprising the dhoti, chadar and the paguri (turban) and the female costume comprising the ghuri, chadar and kanchi (waist cloth). Traditionally the costumes were of white or raw silk color with use of red, blue and yellow for specific dance numbers. In earlier times velvet and satin materials were mostly used for the costumes. With change of time, as this dance form evolved from the sattras onto stage, the design and materials of the dance costumes changed. Pat (also spelled paat) – a silk produced in Assam which is derived from the mulberry plant and muga silk (golden silk of Assam) is also used in preparing the dance costume. Other bright colours are also used in the female costumes. These hand-woven materials normally have intricate local motifs like Kingkhap, Miri Motif, Kolka etc.
Uses of play-specific costumes are also seen in Sattriya dance. The dress of Krishna Nritya and Nadubhangi Nritya is of yellow and blue keeping in line with the attire of Lord Krishna. The Sutradhar Nritya also has its specific white costume with a special turban.
Traditional Assamese jewellery is used in Sattriya dance. The jewellery is made by a unique technique in Kesa Sun (raw gold). Artistes wear Kopali on the forehead, Muthi Kharu and Gam Kharu (bracelets), different type of neck pieces like Mata Moni (for male dancers), Golpata, Dhulbiri (shaped like the musical instrument dhol), Bena (pendant shaped like a crescent), Jethipata (lizard shaped), Dugdugi (leaf shaped), Senpata (eagle shaped), Dhansira (strand of rice grain) and Lokaparo (pigeon design). Earrings are made in similar designs and also Thuka Suna and Keru are worn by dancers. Female dancers wear white flowers in the hair.
The costumes of Ankiya Naats (dramas) are colourful and character specific. Use of Mukha (Masks) to depict demons and special characters are also unique of this dance form. The art of mask-making is an integral part of Sattriya culture and originated in the Sattras of Assam. Beautifully decorated turbans and crowns made by the local artisans are used in the Ankiya Naats.
The facial makeup of Sattriya dance resembles other classical dance forms of India. However, in earlier times traditional materials and herbs were used for make up.
Sattriya Nritya is accompanied by musical compositions called bargeets (composed by Sankardeva and Shree Shree Madhavdev, among others) which are based on classical ragas.
A key musical instrument that accompanies a Sattriya performance is the khol (two-faced, asymmetrical drum quite different from the rest of India) played with fingers. The special shape and materials of construction – clay, wood, leather, rice dough, iron filings, rope straps – of Sattriya khol produces a high pitch with the right side (Daina), while producing a deep bass sound on the left (Bewa).
Accompanying the khol are various types of Tālas or cymbals (Manjira, Bhortal, Bihutal, Patital, Khutital) and the flute (bansuri). Other instruments like the violin and the harmonium have been recent additions.[note 1]
A Sattriya performance comes in many styles such as the Sutradhara (or Sutra-bhangi), character specific Bhangi, Prabesh, Nritya and Jhumura. The Sutradhara is a style that tells a story and presents the spiritual values of Vaisnavism in a complete classical format: nritta, nritya and natya. One feature of the Sutradhara (or Sutradhari) style is the included commentary for the audience in local language.
Ankiya Nat is a subgenre consisting of one-act plays of Sattriya. These are dedicated compositions but feature a ballad, dance and drama.
The character specific different styles of Sattriya have their own costume variations, and focus on the various life stages and activities of Radha, Krishna and the gopis.
Quote: "A summation of the signal importance of the Natyasastra for Hindu religion and culture has been provided by Susan Schwartz, "In short, the Natyasastra is an exhaustive encyclopedic dissertation of the arts, with an emphasis on performing arts as its central feature. It is also full of invocations to deities, acknowledging the divine origins of the arts and the central role of performance arts in achieving divine goals (...)".