Coat of Arms of Montenegro was changed by an act of Parliament in 2004.
It represents the two-headed eagle in flight, of the House of Petrović-Njegoš, a symbol of Byzantine and ultimately Roman origin. Its symbolizes the unity of Church and state, that is: either the unity, or the close connections between the Church and the state. The motif was used by the medieval rulers of Zeta – the House of Crnojević, as well as various other European dynasties. The layout of the Montenegrin coat is copied from that of the Russian Empire, with which the ruling family of Montenegro had close dynastic and political ties in the 19th century when the coat was adopted.
The lion passant in the centre is a sign of episcopal authority and represents the Biblical theme of the Resurrection, or Christ Victorious (Christos Pantakrator, the Lion of Juda). It is derived from the same motif present in the arms of Venice, which had considerable influence in the history of the area. After Montenegro regained its independence and was liberated from the failing Serbian state, it gradually became a theocracy in order to preserve unity before numerous Turkish invasions of the country. For this reason, the authority of the church was reflected in various insignia of the age. After the establishment of the secular dynastic succession in 1851, the lion was placed beneath the eagle, while the initials of the ruler stood on the shield: notably, that of Danilo I, Prince of Montenegro, Danilo II, Prince of Montenegro and King Nicholas I of Montenegro. Curiously, Danilo I was still a prince-bishop while the standard bearing his initials was used. The modern coat of arms placed the lion d’or back on the shield, erasing that monarchic symbol. Today, Montenegro is a secular, democratic republic, so the fact that the crown of the Petrovic-Njegos dynasty was also represented created some controversy at the time of its adoption. However, this solution proved extremely popular and the coat of arms can be seen not only in schools, government offices, etc., but in many private houses, places of business, and private universities and is a common display of national pride.