Task: Question Answering
Input (English): Passage: Johann Sebastian Bach composed the secular cantata Die Zeit, die Tag und Jahre macht (Time, which day and year doth make), BWV 134.1, BWV 134a, while he was in the service of the court of Leopold, Prince of Anhalt-Köthen. Bach wrote the work as a  serenata for the celebration of New Year's Day 1719.
The libretto by Christian Friedrich Hunold, an academic at the University of Halle, takes the form of a dialogue between two allegorical figures, Time and Divine Providence, representing the past and future, respectively. Bach set the words in eight movements consisting of alternating recitatives and arias, culminating in a choral finale. Most movements are duets of solo voices, an alto as Divine Providence and a tenor as Time. Even the closing movement features long duet passages, leading to parts for four voices. The singers are supported by a baroque instrumental ensemble of two oboes, two violins, viola and continuo. The character of the music is close to baroque opera, including French dances.
Later, in Leipzig, Bach used the secular cantata as the basis for a church cantata for the Third Day of Easter 1724, Ein Herz, das seinen Jesum lebend weiß. In the initial version of the Easter cantata, he made no changes to the 1719 music other than to omit two movements and replace the text with words for the occasion, written by an unknown author. In an adaptation for performances in the 1730s, he composed new recitatives for the Easter texts and made further changes to the music.
The cantata, written for a specific occasion, has been performed and recorded rarely, compared with other Bach cantatas. It has been used for congratulatory events such as the 80th birthday of Bach scholar Alfred Dürr, when the cantata title was chosen as that of an international conference about chronology in Bach's music, on which Dürr had focused. 
Question: What is the last name of the person who studied Johann?
Output (English): Dürr.