In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
One example: The Inheritance Cycle is a series of fantasy books written by Christopher Paolini.
Solution is here: The Inheritance Cycle is a tetralogy of young adult high fantasy novels written by American author Christopher Paolini.
Explanation: The output sentence elaborates on the input sentence without changing its general meaning e.g. "tetralogy of young adult high fantasy novels".

Now, solve this: He was the son of Walter Stewart and Marjorie Bruce .
Solution:
He was the son of Walter Stewart , 6th High Steward of Scotland and of Marjorie Bruce , daughter of the Scottish king Robert the Bruce by his first wife Isabella of Mar .