The legislative power of the Caliph (or later, the Sultan) was always restricted by the scholarly class, the "ulama", a group regarded as the guardians of Islamic law. Since the law came from the legal scholars, this prevented the Caliph from dictating legal results. Sharia rulings were established as authoritative based on the "ijma" (consensus) of legal scholars, who theoretically acted as representatives of the Ummah (Muslim community). After law colleges ("madrasas") became widespread beginning with the 11th and 12th century CE, a student often had to obtain an "ijaza-t al-tadris wa-l-ifta" ("license to teach and issue legal opinions") in order to issue legal rulings. In many ways, classical Islamic law functioned like a constitutional law.