It took transposing a genealogical tree for the Golitsyns/Galitzines to Microsoft Word and running a search for "Maria Ilyinichna Dolgorukova" to find anything about her and here it is, "Pr Mikhail, chamberlain 1857, ambassador in Spain (1856-60), *St.Petersburg 25.5.1804, +Montpellier 17.3.1860; m.Moscow 23.8.1842 Pss Maria Ilyinichna Dolgorukova (*1822, +Harbin 30.12.1907).” She had two sons. This explains how she was portrayed by Federico de Madrazo y Kuntz, although the date could be off, unless they were already in Spain before being appointed Ambassador.
She got around. She died in Harbin. Harbin? According to Wikipedia, "Harbin is the capital and largest city of Heilongjiang province in the northeastern region of the People's Republic of China…"
From pinterest.se/anavegamedina5/retratos-de-federico-de-madrazo-y-kuntz/. Also posted to the Iberian Style Between 1837 and 1870 Album here.