A new national system of written exams for monks was introduced in 1911, known as the Mahamakut system to raise the standards of doctrinal learning. Prince Wachirayan's "Nawakowat" was used as the main textbook. It remains an influential textbook in Thai Buddhist doctrinal studies today. The examinations were divided into two levels, ordinary (which focused on doctrine, not Pali) and advanced (included knowledge of Pali). The textbooks of Wachirayan provided Thai monastics with the means to understand the Buddhist doctrine in their own language.