Please add the following ruling authority for 'Serbia (medieval)'
- Stephen Uroš IV Dušan (1331-1346)
And for 'Serbian Empire'
- Stephen Uroš IV Dušan the Mighty (1346-1355)
- Stephen Uroš V Dušan the Weak (1355-1371)
Also, possibly remove the Serbian Empire subgroup in Serbia (medieval) ruling authorities


Comment: Stefan Uros IV ruled as a King from 1331-1346 and as an Emperor from 1346-1355