I am looking for the names of the parents of a Muscovite Princess
called Sophia Holszanka, who is the mother of the Polish king Casimir
IV.

Dear ghisbrando-ga,

There appears to be variations of the spelling of her name and that of
her parents, but three separate genealogical web sites provide her
parents? names. These are extracts of these sites, I suggest you refer
to them to see the family trees in their entirety.

"Ancestors of Kazimierz IV Jagiello, King of Poland
2. Wladyslaw II Jagiello                                                
            King of Poland 1386-1434, Grand Duke of Lithuania                   
            Born circa 1351                                                     
            Died 1 June 1434 Grodek                                             
            Married 7 February 1422                                             
3. Zofia (Sonka) Holszanska                                             
            Born circa 1405                                                     
            Died 21 September 1461
[...]
6. Andrzej Iwanowitsch                                                  
            Prince of Kiew                                                      
            Born 1380                                                           
            Died 1418                                                           
7. Alexandra Dimitrijewna Drutskoy?
http://worldroots.com/brigitte/famous/c/casimir4polandanc1427.htm


"Married (4) Sophie of Kiev
Zofia Holczanska, daughter of Andrzej Iwanowitsch, Grand
Duke of Kiev and Alexandra Dimitrijewna von Druck
Born circa 1405
Died 21 September 1461"
http://worldroots.com/brigitte/famous/o/olgierdlithuaniadesc.htm



"The PEDIGREE of Sofia of HOLSZANY aka Sophie d' HOLSZANY; aka Zofia
von HOLSCANY; aka Sofiya of GOL'SHANY"
http://freepages.genealogy.rootsweb.com/~jamesdow/s073/f165673.htm

"The PEDIGREE of Andrzej IWANOWITSCH von HOLSZANY aka Andre (Andrej)
of HOLSZANY (GOL'SHANY)"
http://freepages.genealogy.rootsweb.com/~jamesdow/s046/f331347.htm


"HOLSZANSKA, Zofia Sexe: Féminin
    Naissance : vers 1405
    Décès : 9 octobre 1461
    Parents:

Père: de KIEV, Andrzej Ivanovitch
Mère: DRUTSKOY, Alexandra Dimitrijewna

Enfant(s):

JAGELLON, Casimir IV

Google cache only
http://216.239.59.104/search?q=cache:VWk9YTn6pF0J:perso.wanadoo.fr/emmanuel.hamel/dat93.htm+zofia+Holszanska&hl=en


I hope this answers your question. If it does not, or the answer is
unclear, then please ask for clarification of this research before
rating the answer. I shall respond to the clarification request as
soon as I receive it.
Thank you
answerfinder


Search strategy
Limited response on ?Sophia Holszanka? led me to try Zofia as an alternative.

Great answer and very fast as well.

Dear ghisbrando-ga,
Thank you for the tip. Pleased I could help.
answerfinder-ga