As Muslim institutions of higher learning, the madrasa had the legal designation of waqf. In central and eastern Islamic lands, the view that the madrasa, as a charitable endowment, will remain under the control of the donor (and their descendent), resulted in a "spurt" of establishment of madaris in the 11th and 12th centuries. However, in Western Islamic lands, where the Maliki views prohibited donors from controlling their endowment, madaris were not as popular. Unlike the corporate designation of Western institutions of higher learning, the waqf designation seemed to have led to the exclusion of non-orthodox religious subjects such a philosophy and natural science from the curricula. The madrasa of al-Qarawīyīn, one of the two surviving madaris that predate the founding of the earliest medieval universities and are thus claimed to be the "first universities" by some authors, has acquired official university status as late as 1947. The other, al-Azhar, did acquire this status in name and essence only in the course of numerous reforms during the 19th and 20th century, notably the one of 1961 which introduced non-religious subjects to its curriculum, such as economics, engineering, medicine, and agriculture. It should also be noted that many medieval universities were run for centuries as Christian cathedral schools or monastic schools prior to their formal establishment as universitas scholarium; evidence of these immediate forerunners of the university dates back to the 6th century AD, thus well preceding the earliest madaris. George Makdisi, who has published most extensively on the topic concludes in his comparison between the two institutions: