Chair of Sacred Letters as well. While at the university, he translated classical and biblical literature and wrote on religious themes. He was widely known for his works. Imprisonment In 1571 Dominican professors Bartolomé de Medina and Castro put forth seventeen propositions to the Inquisition documenting Fray Luis' allegedly heretical opinions. His translation into Spanish and commentary of the Song of Solomon was the biggest evidence presented for their case against him. Another charge touched on his criticizing the text of the Vulgate. As a result, he was imprisoned at Valladolid from 27 March 1572 until December 1576, fell ill and remained in bad health throughout his imprisonment. Though he suffered greatly from his isolation and less than desirable conditions, Fray Luis continued to actively write and study during his confinement. At the end of 1576, the tables turned, and on 11 December Fray Luis was cleared of all charges and released from prison with an admonishment to be more careful and reserved in his publications and speech. He returned to Salamanca on 30 December in triumph. Tradition has it that he began his university lecture on 29 January 1577, his first after returning from four years' imprisonment, with the words Dicebamus hesterna die ("As we were saying yesterday...."). Later life Fray Luis continued to teach at the university, being awarded a special chair at the end of 1576, shortly after his acquittal. In 1578 he obtained, for life, the chair of Moral Philosophy, and in 1579 was elected to the most significant chair in the university, the Chair of Holy Scripture (sometimes known as the chair of Biblical Studies or the Bible Chair). He went on to earn a Master of the Arts degree from the University of Sahagún. Fray Luis did not pay heed to the cautionary admonishments of the Inquisitorial committee after his earlier imprisonment. In 1582, he had another Inquisitional run-in, following three disputations held on the subject of the merits of Christ and human predestination, but was not this time imprisoned. He was absolved two years later, in 1584. Fray Luis's first published Spanish and Latin works emerged in 1580, some having been begun in prison; most of his works were printed during this decade. Between 1583 and 1585 he published the three books of his celebrated treatise, The Names of Christ, which he had written in prison. In 1583 also appeared the most popular