Two streams of development of Svarajati and Varnam should be considered, i.e. development in music and in dance.
Musicologists connect invention of Svarajatis and later Varnas with development of Raga system and the emergence of compositions intended for codification of Raga Lakshana. In the time of Sangita Ratnakara, the Gitis were used for this purpose. Later on, Sangita Pitamaha Purandaradasa composed Keertanas, Suladis Gitis and Tanas, as part of his Abhyasa gana system. Later on, following development of Raga system, invention of Melakartas by Venkatamakhi, emergence of new ragas by composers (Kshetrayya, Tyagaraja, for instance), the new format was required.
According this theory, in music Svarajatis and Varnas were developed independent of each other. Svarajatis used in Abhyasa gana are results of development and transformation of earlier Lakshana gitis, and famous Svarajatis of Syama Sastry are the summit of development of this form in music. Tana varnas were introduced as the "next generation” of Raga Lakshanas based on Chitta tanas (or Kuta tanas) introduced by Purandaradasa and later on used as Raga Lakshanas by veena players. Chitta tana became popular around the beginning of 18th century (Tanjore as seat of music by Dr. Seetha, Citta tana, p. 348), thus preceded and possibly affected development of Tana varnas.
Musicians were searching for appropriate musical format to capture and preserve the grammar of raga. In Sangita Ratnakara simple gitis are used to illustrate Jati lakshanas. Using those gitis as simple melodic examples, Saringadeva illustrated lakshanas of 18 Jathis of ancient Gandharva system.
In ancient system of Grama-Murcana-Jati, the tonic (fundamental tone or sruti in present sense) was variable. Music mode (Murcana) could start from any note. There were two basic scales (Sadja and Madhyama gramas), each having seven Murcanas. Each of eighteen Jati in this system represents a set of rules (Lakshana). Jati is close of the concept of Raganga or Grama raga, which defines family of ragas united under the most famous raga (Raganga).
During medieval period, ancient system of Murcanas gave place to the new system, where the fundamental frequency (tonic) was fixed. The number of svaras was at first increased because of introduction of Sadharana svaras (additional svaras, not resent in ancient basic scales), and then reduced back to twelve in order to systematize the immense diversity of ragas and develop Melakarta scheme.
Concept of Raga underwent further development and went far beyond the ancient concept of mode or Jati (family of modes). Raga is more complex entity then mode. It implies special harmonic (microtonal) relations between the notes. Thus, the order (krama) of singing the svaras, the manner of singing svara (gamakas), relations between the svaras (vadi-anuvadi-samvadi), characteristic combinations of svaras, "profuseness" or "weakness" of svaras (alpatva-bahutva) – all those fine characteristics required to be represented in a composition in order to outline Raga Svarupa.
Thus, Svarajati containing Pallavi and Charanams, with simple sahityam, set to distinct tala used in practical music, was introduced instead of lakshana gitis. Svarajatis of Syama Sastri are the utmost developed master-pieces of this form.
Further on, in the context of veena Chitta tanas were used to record Raga lakshanas. Tana varnam was probably preceded with a class of technical compositions called “Chitta tanas” used in veena concerts. Function of Chitta tanas is to demonstrate all possible movements of raga. Chitta tanas were used as Raga Lakshanas in context by veena players. Chitta tana became popular around the beginning of 18th century. Manuscripts belonging to 18th and 19th centuries contain tanas for common and rare ragas like Salaganata, Nadanamakriya, Nata, Anandabhairavi and others. ( ) In Sangita Sampradaya Pradarshini, many Tanas of Venkatamakhi are notated as Lakshanas for such ragas as Bhanumati (mela 4), Manoranjini (mela 5), Tanukirti (mela 6), Sanagrani (mela 7), etc.
Tana Varnam was introduced in Abhyasa and Sabha gana practice in 18th century AD which is up to now serves as the grammar of Raga.
There are several theories regarding birth of “dance” Svarajati as independent composition. One theory suggests that such musical form as Svara Pallavi. The structure of Swara Pallavi resembles Svarajati in certain aspects. Svarajati could be regarded as the form derived from older Svara Pallavi composition by adding Sahityam to Pallavi and Caranas (Satyanarayana Rao).
“Svara Pallavi” or the song without words is a composition with Pallavi, Anupallavi and several Caranams without Sahitya (with a few exceptions in which only Pallavi has Sahitya.) Svara Pallavi is sometimes supported by Jathis or Shabdams (words of praise) mixed up with svara sequences (this feature is found later on in Svarajatis). Svara Pallavis were performed by vocalists and veena players.
Another theory is based upon historical review of composers who invented the form of Svarajati. They were closely connected with dance, in form of dance dramas such as Bhagavata Mela and Yakshaganas, and in form of court solo dance performances. Such forms as Daru and Prabandha were widely used in both the formats during Maratha period. In Nirupana of Raja Serfoji, Svarajati and Varna have two distinctly different formats. Thus, those compositions could be developed independently, based such earlier forms as Daru and Prabandha, which were employed in music and dance kutcheris during the early medieval period.
Darus inherited many features of Dhruva Prabandhas of ancient Sanskrit theater. They were widely used in medieval dance dramas. Daru is very diverse composition. Most obviously, the term “daru” like the term “prabandha” itself, is very generic. The term “Daru” was used to denote very wide class of compositions used in dance dramas of Bhagavata Mela, Yakshagana, Kuravanji, etc. Existence of numerous varieties of darus prove this idea.
Another possibility is, that Svarajati was developed based on Shabdams. Shabdams are rhythmic composition where Sahitya is alternated with Jathis. They were employed in dance long before Svarajati came into dance repertoire. Famous composer of Shabdams was Natyacharya Kashinatayya of Melattur (V. Raghavan). Sahitya of sabdam is defined as “Yasogiti” or panegyric in praise of God, king or patron. The elements of Yasogiti are also found in later Svarajatis and Varnas. By amalgamating Shabdam and Korvei or Jati (which was Suddha Nritta composition performed after abhinaya composition as Shabdam), ancient Natyacharyas would create the first prototypes of Svarajatis.
New forms of compositions, developed by composers, were employed in dance. Natyacharyas were prolific composers, singers and musicians. Similar to the logic of development of Tana varnam as grammar of raga, emergence of Pada varnam in dance could be considered as evaluation of the grammar of dance.
Dr. Durga suggested that development of Varnam was influenced by such earlier forms as Shabdam and Padam. The major theme is Shabdams is “Yasogiti” or praise of deity, king or patron. The subject of Padams is Nayaka-Nayaki bhavam or relationship. Pada varnas include both those features. The Padas of Kshetrayya, composed in Telugu and having sringara as the main theme, influenced the form of Pada varnam.
“It may be said therefore that the modern Varna forms have emerged from early 18th century. Varna composition of the modern times relates to such forerunning forms as Pada, Svarajati and Sabdam." (S.R. Jayasitalakshmi)
Composers of Pada varnas were either Natyacharyas (like Bhagavata Mela lineage of composers or Tanjore Brothers) or court vidvans, from whom court dancers studied music (like in case of Tanjore Kamalam who was disciple of Muthuswami Dikshitar.) Dance was integral part of court performances. Dance dramas were also indispensable part of temple festivals, for instance, Bhagavata Mela Natakas, Kuravanji and Ula natakas, Krishnaatam and Kudiyattom natakas of Kerala, and even lesser forms such as Kauthuvams, Mallari, Pushpanjali performed as part of temple rituals. Community of performers of those days, in Tamil Nadu, Andhra and Kerala, comprised of dancers, musicians and poets, for instance, Chinna and Peria Melas of Tanjavur, Nambiyars, Chekkiyars and Nangiyars of Kerala. Dancers studied music from famous musicians, and very often were outstanding singers themselves. The later great examples of this tradition are Veena Dhanammal and Bamgalore Nagaratnamma.
Note: Muthuswami Dikshitar composed Telugu pada varnam Rupamu Juchi (Todi) for debut of Thiruvarur Kamalam, hereditary danseuse attached to Tyagaraja temple who studied music from him. This varnam was added with the daru “Nee Sati Deivamu” in Sriranjani raga in praise of the Lord. Tiger Varadachariar composed Telugu sahitya for the Muktayi svaras and the swaras in the charanam of this Pada varnam later.
Varnam could be result of amalgamation of two formats. Two sections of Varna represent two kinds of compositions, which could possibly affect the emergence of the varna:
Varnam is wonderful example of collaborative work of dance masters and composers. Musicians wanted to paint the live picture of raga, to create a perfect vehicle, which could envelop the very essence of raga in a few passages of swaras and few lines of sahitya, like slokas of Vedas contain major philosophical ideas. Natyacharyas put great effort to make rich contents of the Varnam visible. They developed the composition, which gives room for each element of dance, including music, rhythm, sahityam and visual presentation of rhythm in pure movement and music and sahityam in expressive acting.