A study for the fresco 'The sybils'

A photograph of a drawing by Raphael in the Albertina, Vienna (inv.no.17573) which is a study for the angel holding a scroll, with the arm of the sybil below, on the far left-hand side of the fresco The four sibyls painted by the workshop of Raphael c.1511-14 in the Chigi Chapel in Santa Maria della Pace, Rome. Annotated on verso.

Raphael was commissioned, probably early in 1511, by the banker Agostino Chigi to decorate his chapel in Santa Maria della Pace. The initial plan of decoration for the chapel included frescoes, two bronze roundels and an altarpiece; however, whilst Raphael executed some designs for the altarpiece, which was to depict the resurrection, it was never executed, and the bronze roundels, whilst cast, appear to never have been installed. The frescoes comprise two registers, with four prophets on the top  (flanking a window) and four sybils below. According to Vasari, portions of the frescoes were painted by Timoteo Viti.