Two official Serb tricolor flags of Montenegro above Prince Nikola I Petrovic Njegos and his wife Milena on commemorative postcard issued for the 40th anniversary of Nikola's Coronation and Wedding.

Four official Serb tricolor flags of Montenegro above Prince Nikola I Petrovic Njegos and his wife Milena on commemorative postcard issued for the 40th anniversary of Nikola's Coronation and Wedding.

Nikola I celebrated the 50th anniversary of his rule by crowning himself king and proclaiming Montenegro a kingdom.