His involvement came to an end in 1985, when Hans-Caspar Graf von Bothmer (University of Saarland) took over as the local director.
Bothmer left Ṣan'ā' in the following year, but continued to run the project from Germany, traveling to the site almost every year.
A partial reconstruction of the lower text was published in 2012; and a reconstruction of the legible portions of both lower and upper texts of the 38 folios in the Sana'a House of Manuscripts was published in 2017 utilising post-processed digital images of the lower text.
In 1972, construction workers renovating a wall in the attic of the Great Mosque of Sana'a in Yemen came across large quantities of old manuscripts and parchments, many of which were deteriorated.
Of the remaining 1500–2000 fragments, he microfilmed a group of 280.