At that time, there was a custom where family heads or sons of prestigious families, including the Fujiwara family, were automatically given official ranks, regardless of their ability, when they reached a certain age.
藤原氏をはじめとして名家の子弟や家長などは、一定の年齢に達すると、その実力とは別に、自動的に官位が与えられるのが慣習となっていた。