Durgasimha is the author of Durga Vritti, the earliest commentary on the Katantra grammar of Sarvavarman (another text like Panini’s grammar). Durgavritti provides a systematic study of Katantra grammar and gives explanations wherever necessary. Durgasimha in his work has dealt with the views of all his predecessors in Purvapaksha and presents his views in the ‘siddhanta’ section. Specialists in this field of grammar unanimously feel that vritti has done as much service to Katantra grammar as mahabhashya has done for Panini’s grammar.
Durgasimha is also known as Durgatma, Durga and Durgapa. There is no certainty about his date, as he does not provide any details about his personal life in his work. However, oriental scholars give different views on his date. A.B. Keith assigns him to the 10th century CE (NCC, Vol.III.p.309a); Balvelkar assigns him to the 8th century CE., since Durgasimha knew Candradhatupatha and is quoted by Hemacandra. Yudhishthira Mimamsaka assigns him to 600-80 CE, because Durgasimha quotes Bharavi and Mayura (who lived in the 6th century CE and the 7th century CE respectively and he should be earlier than Kasikavritti (700 CE) as Vamana, its author criticizes the views of Durga.
There are different views regarding his identity also.
While S.K. Belvelkar is of the opinion that Durgasimha who wrote the commentary of Katantra, is different from the commentator of Nirukta and the author of Linganusasana (of Katantra School). Yudhishthira Mimamsaka holds the view that the commentator of Nirukta and the author of Durgavritti are one and the same. S.K. Belvelkar also holds the view, which is accepted by the scholars that Durgavritti and Durgavritti Tika are by different authors of same name.