Vasi, Giuseppe (1710-82; Italian)
Pius VI in procession in St Peter’s 1775
Etching, c.70.2 x 96.8 cm (plate)
Acquired 1868
Location unknown

A work noted in the NGV’s list of pre-Felton acquisitions, as “A Solemn Procession in Saint Peter’s, Rome, 1775” (artist not named), is almost certainly identifiable as the print detailed here. It was acquired with two etchings by Piranesi (also no longer in the collection).

The Getty provides detailed information on its impression of the present print, noting that Vasi, born in Sicily, moved to Rome in 1736. The NGV holds a volume of his Roman vedute (acquired in 1952).

The grand procession depicted was staged to mark the jubilee year of 1775. Pius VI, of aristocratic birth, was Pope from 1775 until his death in 1799. After resisting Napoleon’s advance on Rome, he was arrested and transported to France in 1798.

Refs.

PF no.328 (acc.no.p.179.2-1), as acquired in 1868 

For Vasi, see e.g. https://en.wikipedia.org/wiki/Giuseppe_Vasi. For the Getty print, see http://www.getty.edu/cona/CONAFullSubject.aspx?subid=700001180 (entry dated 2004); an ID photo is available at https://www.alamy.com/pius-vi-in-procession-in-st-peters-during-the-holy-year-of-1775-image268799427.html (Smith Archive) 

For Pius VI, see e.g. https://en.wikipedia.org/wiki/Pope_Pius_VI (with references). I have yet to see a copy of Jeffrey Collins, Papacy and Politics in Eighteenth-Century Rome: Pius VI and the Arts, Cambridge UP, 2004

See also https://www.ngv.vic.gov.au/explore/collection/work/42649/ (for Vasi’s Raccolta delle piu belle vedute antiche di Roma, Vol.I, donated to the NGV by Mrs Snodgrass, 1952; not reproduced) [all websites noted consulted 25 May 2020]