Sahih al-Bukhari 6206
Narrated Abu Huraira:
The Prophet (ﷺ) said, "The most awful (meanest) name in Allah's sight." Sufyan said more than once, 
"The most awful (meanest) name in Allah's sight is (that of) a man calling himself king of kings." 
Sufyan said, "Somebody else (i.e. other than Abu Az-Zinad, a sub-narrator) says: What is meant by 
'The king of kings' is 'Shahan Shah.,"
حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا سُفْيَانُ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، رِوَايَةً قَالَ ‏
"‏ أَخْنَعُ اسْمٍ عِنْدَ اللَّهِ ـ وَقَالَ سُفْيَانُ غَيْرَ مَرَّةٍ أَخْنَعُ الأَسْمَاءِ عِنْدَ اللَّهِ ـ رَجُلٌ تَسَمَّى بِمَلِكِ الأَمْلاَكِ ‏"‏‏.‏ قَالَ سُفْيَانُ يَقُولُ غَيْرُهُ تَفْسِيرُهُ شَاهَانْ شَاهْ‏.‏