Dear Bhante Dhammanando, Jim V747 and Stephen,

Jim V747 wrote: The Buddha was occasionally referred to as the "Kinsman of
the Sun".

>> Does anyone know how this phrase originated?

N:See Buddhist Proper names, King Mahaasammata, the original ancestor of the
Saakyan family... belonged to the Solar race...
We read in the Co. to the Mahaaraahulovadasutta:
<bhagavaapi mahaasammatapave.niya.m okkaakaraajava.mse jaato,
raahulabhaddopi.

Both the Exalted One and Lucky Rahula were born into the royal dynasty of
King Okkaka, descending from King Maha-Sammata.

bhagavaapi sa"nkhe pakkhittakhiirasadiso suparisuddhajaatikhattiyakule
jaato,
raahulabhaddopi.

Both the Exalted One and Lucky Rahula were born into the warrior clan, a
superior family, pure like milk put into a conchshell.>

Nina.