Was Shvarno the nephew of Mindaugas? Some sources state Anna of Novgorod as his mother but Daniel of Galicia was also married to Mindaugas's sister and that would make more sense.
From tracing back their ancestry Shvarno and his brother appear to be related through their father to the Anglo Saxon King, Harold Godwinson and his wife Edith Swan Neck.
Harold fought William of Normandy (William 1) at the battle of Hastings and was killed. Edith searched the battlefield for his body which was that bady mutilated she could only identify him by marks that were known to her alone.
So it appears that Shvarno had Royal Saxon blood through the daughter of Harold and Edith Swan Neck, Gytha.
It is also possible to trace Gytha's descendants through to the present day British Royal Family. Her ancestry possibly goes back to the very early West Saxon Kings. Strange that she left England after the Norman invasion but her ancestors married into the European and British royal families.
Harold and Edith Swan Neck were a very attractive couple by all accounts. Had they lived in today's society they would have been much photographed.
I have previously seen the line between Gedminas and the British Royal family but was unaware of the connection between the Saxon Kings and the earlier Grand Dukes.
I noticed also that Shvarno's sister Pereyaslava links through to the British Royal family. There is another connection to the Grand Dukes in her chart. Gaudemunda, daughter of Traidenis married Bolesław II of Masovia.