His full name was Alauddin Abu Bakr ibn Ahmad al-Kasani, who was also known with his honourable title “Malik al-ulama” (King of Scholars). By profession, he was a lawyer of the Hanafian order. The books devoted to his life and career do not give enough information about his youth and date of birth.
Kasan was one of the cities situated on the backside of Shash province in Maveraunnahr, on the northern bank of the river Sayhun running through Fergana valley. Due to the name of his birthplace, he was honoured with the title “Kasani”. Some sources misuse this title as “Kashani” but original sources confirm the incorrectness of the latter version. Such an idea was expressed in the works of a German scholar and orientalist Haffe.
Thanks to the greatness of his scientific potential and perfect -ness of his writings,his contemporaries honoured him as “Malik al-ulama” (The King of Scholars). Alauddin Abu Bakr ibn Ahmad al-Kasani came to Bukhara and studied at the school of his teacher Imam Alauddin Muhammad ibn Abi Ahmad as-Samarqandi (died in 1191). There Kasani learned the books with great interest written by his teacher under the titles of “Tuhfatu-l-fuqaha”, “Sharh Tavilat fi tafsir al-Qur’ani al-a’zim” and other books devoted to the description of style and “Furu”. He also listened to the Hadiths cited Irom well-known scholars of his time as well as his teacher Alauddin as-Samarqandi. Alongside with this activity, he wrote commentaries on the book of his teacher “Tuhfatu-l-fuqaha”. Besides, he created his masterpiece “Badon” and presented it to his teacher. Of <ourse, his teacher was very satisfied and glad with this present. I Jnder the request of highly respected matchmakers (there were c-vcn the representatives of Turkish rulers among them), his teacher decided to give his daughter Fatima, who was also scholar and welleducated lawyer,to marry his disciple Alauddin Abu Bakr ibn Ahmad al-Kasani. As payment for this marriage, Alauddin as-Samarqandi accepted the book written by his newly married son-in-law Alauddin Kasani under the title of “As-Sanai”, which contained commentaries on the works of his estimated teacher. Therefore, there appeared a saying among the public that “Having commented on the works of his teacher, Kasani married his daue hter”. After the marriage, Alauddin Kasani, his newly married wife Fatima and their teacher Alauddin as-Samarqandi began to settle the disputable problems of the Islamic law.
In search of science and education, Alauddin Kasani once visited Rome (Caliphate of Ottoman Turks) with his respected wife. In the capital city of the Turkish Cali phate the ruler of the Seljuks Mas’ud (died in 572/1176) received him with great respect. In the city of Konya Kasani had to take part in the debates with the leading scholars and delivered lectures for the students. Once he happened to take part in the heated discussions with a leading scholar Sha’rani, who .promoted an idea that everyone who made citations from Abu Hanifa was right in regard with them and so tried to prove his tightness. Kasani said that those who cited from Abu Hanifa might have been right or wrong in regard with their citations and only one of them could have been reliable. Kasani said that Sha’rani’s ideas were based on the Mu’tazilah teachings and proved the correctness of his idea. During the heated discussion, Kasani got angry about the ideas stubbornly defended by Sha’rani and wanted to whip him. Being offended of Kasani’s attitude towards him, Sha’rani complained to the ruler of Konya and the ruler made orders to exile Kasani from the country. However, in accord with the request of the vizier, the highly respected scholar Kasani was pardoned and sent to Halab to the presence of the ruler Nuriddin a/ Zangi as an ambassador. This event is supposed to have taken place approximately in 541/1146-543/1148.
Nuriddin az-Zangi was a just and well-educated ruler. He provided peace in the country, paid much attention to the const nu tion of the roads, walls of the citadel, hospitals, madrasahs and. supporting the Sunni order, invited the leading specialists in this field and had lessons delivered based on the teachings of the Hanafian trend. The time when Kasani lived in Halab was a time of rule of the Zangis and Ayyubis; science and education in the country was highly developed. Scientific and educational as well as religious discussions and debates organized in the madrasahs were united as a whole unit of institutions. They supported the teachings and principles of the Sunni order and were directed to fight against the supporters of the Shiite order. Living in Halab, Kasani used to deliver lessons in these educational institutions.
Kasani earned great fame among the religious people in a short period of time in Halab and, in accord with the demands of the religious lawyers, he was appointed by the ruler of the country Nuriddin as Head Master of the newly built madrasah called Halabia. The group of lawyers accepted this act positively and with great satisfaction. Prior to Kasani, a man called Ar-Razi as-Sarakhsi used to work in the madrasah at this position. He used to burr and pronounce the sounds gutturally. The public in the audience was dissatisfied with his speech as they could hardly catch what he had said. When Kasani was invited take that position in the madrasah, as-Sarakhsi was alive. Thanks to his scientific potential and superior knowledge, Kasani earned great fame very soon. People began to respect and surround him. They were eager to listen to him and, even at his absence in the madrasah, they used to spread his praying carpet. When he came, they used to sit around him and did not leave the madrasah while Kasani was there. Being a man of brilliant education and knowledge, Kasani used to lead a ruthless and unprecedented ideological fight against the representatives of different parties and groups in religion such as “Mu’tazilis” and “ahl al-bid’ats”. He used to attract the attention of the participants of the debates stressing that the ideas of his opponents were the same with the supporters of “Mu’tazilis”. Kasani had also visited Syria before and then he used to invite the specialists in the legal matters ol religion to discuss controversial problems of science and religion. He used to say: “Please, bring a controversial problem and we will discuss it”. He used to prove the disputability of the problem under discussion and used to settle these questions from the point of view of the Hanafian law as the scholars of Syria were devoted to the teachings of the Shafi’ya order. In the debates, he used to speak slowly with assuasive voice and tried to persuade his opponents in the rightness of his ideas, and came out of the discussions as a victorious winner.