The successors to Mohammed split into two major families, and contested to be his succors, launching war against each other, as persists to this very day. There were also sects within these two branches which further complicates the problems, rather similar to the splits in Christianity, though in very recent years, they have desisted (or forced to desist) from open conflict and violence.
Abbasid caliphate -- Baghdad Ummayyad Caliphate- Cordoba
No and they are still seprate countries
The Abbasid Caliphate declined due to a combination of internal strife, economic difficulties, and external pressures. Political fragmentation emerged as regional governors and military leaders gained power, leading to the rise of independent dynasties. Additionally, the empire faced invasions from groups like the Seljuks and the Mongols, which further weakened central authority. By the 13th century, these factors culminated in the disintegration of the once-unified caliphate.
An unsuccessful German offensive was Operation Barbosa the invasion of the USSR.
before
A Caliphist is a proponent of a caliphate, a unified Islamic government of the Muslim world.
The loss of the caliphate significantly altered the political and spiritual landscape of Islam, leading to the fragmentation of authority among various sects and states. It diminished the central leadership that had unified Muslims under a single political and religious system, giving rise to diverse interpretations of Islam and the emergence of different schools of thought. This decentralization also allowed for the growth of regional powers and movements, which sometimes led to conflicts and sectarian divisions that are still evident today. Overall, the disappearance of a unified caliphate contributed to a complex and multifaceted global Islamic identity.
Italy became a single, unified nation.
Engand & France were becoming nations unified under a single ruler.
There is no single unified theory that explains all correlated electron systems.
Unified action
Europe has yet to be unified under a single currency.
Abbasid Caliphate.
Rashidun Caliphate was created in 632.
Unified or central government
unified argument
Fascism is a political faction or party in a particular place. There is no single unified party so there is no single leader.