Rajamartanda is a famous commentary on Yogasutra of Patanjali by Bhoja Deva of Dhara (1018 to 1060 AD). Although Bhojadeva, popularly known as Bhoj Raja, was constantly engaged in wars, he was a renowned author and patron of learned men.
Commentator, Ajada, has noted that Bhojadeva had composed 84 books on different branches of knowledge. Of them, there are multiple versions of Rajamartanda and Sarasvatikanthabharana.
Rajamartanda, edited by Rajendra Lal Mitra, 1883, is an important commentary on Yogasutra of Patanjali and is believed to have been written during the earliest years of Bhoja’s reign. Sometimes it follows Vyasa Bhashya. Sri Krishna Chandra was a commentator on this Bhoja Vritti. Al-Beruni (973-1048 AD) perhaps used it while writing his famous work Tahqiq-i-Hind (An Enquiry into India).
Rajamartanda, edited by J.T. Acharya, Bombay, 1924, is a work on the preparation of medicated oils and other medicines. It contains 418 karikas (verses).
Another Rajamartanda is in the form of a manuscript as noted by Prof P. V. Kane. It has 1462 karikas and contains such topics as vows (vratas), marriage (vivahas), sankranti (first day of month according to Vikrami calendar, and Purusha Lakshana (qualities of a man). It is mainly an astrological work related to Dharmashastras. Its commentator is Ganapati.
Raghunandana Bhattacharya (1500 AD) speaks of a brhat (bigger) Rajamartanda. But whether both the works are distinct is not quite clear.
Bibliography
India : Early History (1999) P.N. Chopra – New Delhi Publication Division
Encyclopedia of Hinduism Volume VIII – Page 404 - IHRF