such as Buddhagosa, Dhammapala, Mahanama, Upasena, and Buddhadatta. Buddhagosa writes that he based his commentaries on older works which were brought to Sri Lanka when Buddhism first arrived there, and were translated into Sinhalese. K.R. Norman has written that there is evidence that some parts of the commentaries are very old. Sub-commentaries Sub-commentarial works called Tikas are secondary commentaries, that is to say, commentaries on the Atthakathas. Dhammapala is one early author of tikas. He is particularly known for his Paramatthamañjusa, a sub-commentary on the Visuddhimagga. Doctrinal Manuals, Summaries and Treatises Visuddhimagga - Buddhaghosa, A very influential compendium of Buddhist doctrine and practice by Buddhagosa (5th century). Abhidhammavatara - Buddhadatta, The earliest effort at an introductory manual which summarizes the doctrines in the Abhidhamma (5th century) Ruparupa-vibhaga - Buddhadatta - A short manual on Abhidhamma (5th century) Saccasankhepa - Culla-Dhammapala, "Elements of Truth", A "short treatise on Abhidhamma" (7th century) Abhidhammattha-sangaha - Acariya Anuruddha, A summary of the Abhidhamma, widely used as an introductory Abhidhamma text, c. 11th to 12th century. Namarupa-pariccheda - Acariya Anuruddha, A verse introduction to the Abhidhamma Paramattha-vinicchaya - attributed to Acariya Anuruddha, K.R. Norman thinks this might be a different Anuruddha. Khemappakarana - By the nun Khema, A "short manual on the Abhidhamma" Mohavicchedani - Mahakassapa of Chola, A guide to the matikas (topics) of the seven books of the Abhidhamma (12th century) Nāmacāradīpikā - Chappata, (15th century) Vinayavinicchaya - Buddhadatta, A verse summary of the first four books of the Vinaya (5th century) Uttaravinicchaya - Buddhadatta, A verse summary of the Parivara, the final book of the Vinaya (5th century) Khuddasikkha and Mulasikkha - Short summaries on monastic discipline. Upasaka-janalankara - Sihala Acariya Ananda Mahathera, a manual on the Buddha's teachings for lay disciples (Upasakas) (13th century) Simalankara, a work dealing with monastic boundaries (sima) Bhesajjamanjusa - a Medical text from Sri Lanka (13th century) Yogāvacara's manual - Sri Lankan meditation manual (c. 16th-17th century) of Esoteric Theravada (Borān-kammaṭṭhāna). Amatākaravaṇṇanā (c. 18th century) - According to Kate Crosby, this is one of the most extensive manuals of Esoteric Theravada meditation and was compiled by Kandyan Sinhalese students of Thai esoteric meditation masters. Historical Chronicles The following include various Buddhist historical chronicles (vamsa): Dipavamsa - "The Island Chronicle" (4th century) Mahavamsa - "The Great Chronicle" (6th century) by Mahanama A Cambodian Mahavamsa, almost twice the length of the original, and including numerous additions. Culavamsa -