At the Universidad de Zaragoza Asín had met and begun study under the Arabist Professor Julián Ribera y Tarragó. In 1896 at Madrid he defended his thesis on the Persian theologian Ghazali (1058–1111) before Francisco Codera Zaidín and Marcelino Menéndez y Pelayo. All three professors guided his subsequent studies. Asín then developed his study of Al-Ghazali, and published it in 1901. He also wrote on Mohidin Abenarabe, who is often called the leading figure in Islamic mysticism. Thus Asín was running parallel with a then European-wide effort to understand Muslim inner spirituality.