In this artwork, how is the Borghese collection of the Provenance elucidated?
The paintings were still recorded as part of the Borghese collection in 1693, as a small inventory number 118 at the bottom left of the London Julius shows. The discovery of this number, hidden by over-paint, in x-ray photographs in 1969 was one of the key pieces of evidence establishing the primacy of the London version.  It matches a catalogue of paintings in the Palazzo Borghese in Rome in 1693.  The painting presumably left the collection between 1794 and 1797, and its whereabouts are then unknown until it reappears in the Angerstein Collection in London by 1823, and so was acquired by the National Gallery in 1824, initially catalogued as a Raphael, but this attribution was soon abandoned for over a century.
Palazzo Borghese Borghese collection Julius Raphael left Angerstein Collection National Gallery x-ray