Shia Muslims understand the process of "ijtihad" as being the independent effort used to arrive at the rulings of sharia. Following the death of the Prophet and once they had determined the Imam as absent, "ijtihad" evolved into a practice of applying careful reason in order to uncover the knowledge of what "Imams" would have done in particular legal situations. The decisions the "Imams" would have made were explored through the application of the Qur'an, Sunnah, "ijma" and '"aql" (reason). It was not until the end of the eighteenth century that the title of "mujtahid" became associated with the term "faqih" or one who is an expert in jurisprudence. From this point on religious courts began to increase in number and the ulama were transformed by Shia Islamic authorities into the new producer of "ijtihad". In order to produce perceptive "mujtahids" that could fulfill this important role, principles of Shia jurisprudence were developed to provide a foundation for scholarly deduction of Islamic law. Shaykh Murtada Ansari and his successors developed the school of Shia law, dividing the legal decisions into four categories of certainty ("qat"), valid conjecture ("zann"), doubt ("shakk"), and erroneous conjecture ("wahm"). These rules allowed "mujtahids" to issue adjudications on any subject, that could be derived through this process of "ijtihad", demonstrating their great responsibility to the Shia community Furthermore, according to Shia Islamic Jurisprudence a believer of Islam is either a "Mujtahid" (one that expresses their own legal reasoning), or a "Muqallid" (one performing Taqlid of a Mujtahid) and a "Muhtat" (one who acts with precaution). Most Shia Muslims qualify as "Muqallid", and therefore are very dependent on the rulings of the "Mujtahids". Therefore, the "Mujtahids" must be well prepared to perform "ijtihad", as the community of "Muqallid" are dependent on their rulings. Not only did Shia Muslims require: