PAX AMERICANA [ American Peace ]VS ANCIENT PAX ROMANA-- to recent pax Britannica

peace not as an absence of war, but the rare situation that existed when all opponents had been beaten down and lost the ability to resist

Pax RomanaThe Pax Romana began with the accession of Augustus in 27 BC, which marked the end of the Roman Republic and its final civil wars, and lasted until 180 AD and the death of Marcus Aurelius. The Latin word pax, most often translated "peace," also means "treaty" or "accord." The Roman legal system, which forms the basis of many Western court systems today, unified the administration of justice in the courts throughout the provinces. The Legions patrolled the borders with success, and though there were still many foreign wars, the internal empire was free from major invasion, piracy, or social disorder on any grand scale. The empire, wracked with civil war for the last century of the Republic and for years following the Pax Romana, was largely free of large-scale power disputes. Only the year 69 AD, the so-called 'Year of the Four Emperors' following the fall of Nero and the Julio-Claudian line, interrupted nearly 200 years of civil order. Even this was only a minor hiccup in comparison to other eras. The arts and architecture flourished as well, along with commerce and the economy.

Roman Empire at its greatest extent with the conquests of Trajan
During the Pax Romana, the area of Roman rule expanded to about five million square kilometres (two million square miles).soldier-emperor, Septimius Severus, who, despite giving the Empire a peaceful reign, was accused by Gibbon of catalysing the Crisis of the Third Century, a period of economic, political and military crisis that, together with the Germanic invasions and the rise of the Sassanid Persian Empire in the East, almost led the Empire to collapse.

Beginnings of relative peace

The Pax Romana started after Octavion (Augustus) beat Marc Anthony in the Battle of Actium. He became princeps, or "first citizen". Lacking a good precedent of successful one-man rule, Augustus created a junta of the greatest military magnates and stood as the front man. By binding together these leading magnates in a coalition, he eliminated the prospect of civil war. The Pax Romana was not immediate, despite the end of the civil wars, because fighting continued in Spain and in the Alps. Nevertheless, Augustus closed the Gates of Janus (the Roman ceremony to mark world Peace) three times, first in 29 BC and again in 25 BC. The third closure is undocumented, but Inez Scott Ryberg (1949) and Gaius Stern (2006) have persuasively dated the third closure to 13 BC with the Ara Pacis ceremony
The Pax Mongolica 
meaning "MongolPeace" coined by Western scholars to describe the stabilizing effects of the conquests of theMongol Empire on the social, cultural, and economic life of the inhabitants of the vast Eurasianterritory that the Mongols conquered in the 13th and 14th centuries
The expansion of the Mongol Empire

Pax Britannica (Latin for "the British Peace", modelled after Pax Romana) was the period of relative peace in Europe (1815–1914) during which the British Empire controlled most of the key maritime trade routes and enjoyed unchallenged sea power.
The Pax Britannica was weakened by the breakdown of the continental order which had been established by the Congress of Vienna.[1]Relations between the Great Powers of Europe were strained to breaking point by issues such as the decline of the Ottoman Empire, which led to the Crimean War, and later the emergence of new nation states in the form of Italy and Germany after the Franco-Prussian War. Both of these two wars involved Europe's largest states and armies. The industrialisation of Germany, the Empire of Japan, and the United States of America further contributed to the decline of British industrial supremacy following the late 19th century.

An elaborate map of the British Empire in 1886, marked in the traditional colour for imperial British dominions on maps
Pax Americana
From the end of the Napoleonic Wars in 1815 until World War I in 1914, the United Kingdom played the role of hegemon,where the balance of power was the main aim. It is also in this time that the British Empire became the largest empire of all time
During the British hegemony, America developed close ties with Britain, evolving into what has become known as a "special relationship" between the two. The many commonalities shared with the two nations (such as language and history) drew them together as allies. Under the managed transition of the British Empire to the Commonwealth of Nations,
is primarily used in its modern connotations to refer to the peace established after the end ofWorld War II in 1945. In this modern sense, it has come to indicate the military and economic position of the United States in relation to other nations
Regardless, it is acknowledged that American isolationism subsided only after major shocks associated with the Spanish-American War and the two world wars. Critics such as Howard Zinn and Noam Chomsky argue that the United States has sought, or has found itself forced into, a quasi-imperialist role by its status as the world's sole superpower.
American imperialism is a controversial term referring to the influence of the United States. Since the start of the cold war,
More specifically, critics of American influence contend that the Bush Doctrine of advancing democracy throughout all the world is all that is needed to justify the term "American Imperialism",
Though relative peace existed in the Western world, the United States and its allies have been involved in various regional wars, such as theKorean War, the Vietnam War, the Gulf War, the Yugoslav wars, the Afghanistan War and the Iraq War. The United States also maintainedespionage and covert operations in various other areas, such as Latin America in the 1980s.
The increasing peacefulness during the various incarnations of Pax Americana has been attributed to the ongoing spread of democracy.Democratic peace theory hold that democracies rarely, or never, make war on one another and results in a Pax Universalis.