-a bit of background      

                        David Dadiani
David Dadiani, Duke of Dukes of Mingrelia, had four children.

The older two were daughters: 
      Princess Martha Davidovna, born on February 4, 1840
      Princess Nino Davidovna, born on January 2, 1841.
The next two were sons:
      Nikolai Davidovitch Dadiani, born on January 4, 1847
      Andrei Davidovitch Dadiani, born on October 24, 1850.

His two daughters died very young:  Princess Martha in 1842 and Princess Nino in 1848.

Of his two sons:
One would follow in his footsteps and become the final Duke of Dukes of Mingrelia.
The other would become a chess player.
 

The Black Sea forms the western border of  the Georgian province of Mingrelia (Samegrelo). ^{see maps}  Ever since Mingrelia became a Georgian province in the 11^th century, the ancient house of Dadiani governed the province with its militaristic style through a succession of Dukes.  From the 11th through the 16th centuries, Mingrelia was under the Georgian Kingdom which allowed the Dadiani to rule in return for military favors. In the 16th century, Mingrelia gained its independence which it held until 1803 when it was absorbed by Russia under a special agreement that allowed the Dadiani to continue ruling. But the family's days were numbered and in 1857, Tzarist Russia took over the rule of Mingrelia, leaving the Dadiani family their titles.

Edward Gibbon's is his massive book, The Decline and Fall of the Roman Empire, describes old Mingrelia:

Both the soil and climate are relaxed by excessive moisture: twenty-eight rivers, besides the Phasis and his dependent streams, convey their waters to the sea; and the hollowness of the ground appears to indicate the subterraneous channels between the Euxine and the Caspian. In the fields where wheat or barley is sown, the earth is too soft to sustain the action of the plough; but the gom, a small grain, not unlike the millet or coriander seed, supplies the ordinary food of the people; and the use of bread is confined to the prince and his nobles. Yet the vintage is more plentiful than the harvest; and the bulk of the stems, as well as the quality of the wine, display the unassisted powers of nature. The same powers continually tend to overshadow the face of the country with thick forests; the timber of the hills, and the flax of the plains, contribute to the abundance of naval stores; the wild and tame animals, the horse, the ox, and the hog, are remarkably prolific, and the name of the pheasant is expressive of his native habitation on the banks of the Phasis.

                                                                                                                                                                  

^{Mingrelian Coat of Arms}         

Further along he adds something about the people who inhabited the land:

It is in the adjacent climates of Georgia, Mingrelia, and Circassia, that nature has placed, at least to our eyes, the model of beauty in the shape of the limbs, the color of the skin, the symmetry of the features, and the expression of the countenance. According to the destination of the two sexes, the men seemed formed for action, the women for love; and the perpetual supply of females from Mount Caucasus has purified the blood, and improved the breed, of the southern nations of Asia.

                                     Dadiani Castle

While maintaining rule for 800 years isn't easy and in the course of that time there had been  many upheavals. The most irrevocable one occurred in 1803 when, seeking protection against Persia and the Ottoman Turks, Mingrelia allowed itself, through a pact between  Tsar Alexander I and Prince Grigol Dadiani, to be annexed by Russia. The Dadiani remained in control. In 1857, Russia ended this provincial-type government and the rule of the Dadiani ended also.

 The final Duke of Dukes of Mingrelia