In Sri Lanka, what was determined to be the best unifying scripture?
Over the years, various attempts have been made to synthesize a single Buddhist text that can encompass all of the major principles of Buddhism. In the Theravada tradition, condensed 'study texts' were created that combined popular or influential scriptures into single volumes that could be studied by novice monks. Later in Sri Lanka, the Dhammapada was championed as a unifying scripture.
The Pāli Tipitaka is the only early Tipitaka (Sanskrit: Tripiṭaka) to survive intact in its original language, but a number of early schools had their own recensions of the Tipitaka featuring much of the same material. We have portions of the Tipitakas of the Sārvāstivāda, Dharmaguptaka, Sammitya, Mahāsaṅghika, Kāśyapīya, and Mahīśāsaka schools, most of which survive in Chinese translation only. According to some sources, some early schools of Buddhism had five or seven pitakas.