Почему на Руси оказалось два претендента на великое княжение?

284   7          152  5          8164   8                 2042        6
28     40        15    30        8         1020           18            34
    4(ост)           2(ост)         16                         24
                                            16                         24
                                                4(ост)                    2(ост)

8420           6                      8569           9                 37610          4              81610      3
6                 1403                81               952             36                9402        6              2             24                                         46                                                                                         24                                         45                                 16
    20                                       19                                16                                  
   18                                       18                                     10                                                                                      
       2(ост)                                1(ост)                               8   
                                                                                          2(ост)                      

81610        3
6                27203
21
21
   6
   6
     10
       9
        1(ост)