Adam died in Rome, his adopted city, aged around 70. There is some confusion about the date of his death not least because of the inscription on his tomb which can still be seen in the Church of St Cecilia in Trastavere, Rome. An inscription can be found on the tomb today suggesting Adam died in 1398. But the tomb used to have a canopy over it, removed in the 17th century and that tells a rather different story!
The inscription on the canopy of Adam's tomb is preserved in a drawing made of his tomb before the canopy was removed. The drawing can still be found in the Vatican Library records (see Manuscript Barb. Lat. 3084 see folio 282r). Roughly translated the Latin inscription read:
Skilled in all things, renowned father Adam. The great theologian, who was cardinal of England, which was his fatherland, the title of St Cecilia was given to him. He died and ascended to heaven in the year 1397, in the month of September.