Want this question answered?
the catholic church
Both acted as a unifying force in europe
The church.
Oversimplified, the major unifying force of Europe during the middle ages was universal Christianity (both Roman Catholic and Orthodox) providing an us-vs-them mentality in oppostion to their Islamic foes in the Ottoman Empire, the caliphates (abbasid, fatimid, etc.), the Emirate of Cordoba, and Al-Andulas.
The Crusades united Christians in a common cause against a foreign enemy.
The Catholic Church.
Christianity could be considered to be the heir to the Roman empire because after the fall of the west, it was the single unifying force. Christianity did not stop wars nor did it erase ethnic prejudices, but it was the one common thread running through Europe, just as the Roman empire was the common binder of Europe.
The Church was an organization that existed in practically all of medieval Europe. It had its own rules, which it could impose on the governments of countries, and though it did not do this often, it did have the effect of producing a certain level of uniformity in how kings and other leaders dealt with their people. The Church provided much of the education of the Middle Ages, and what it did not provide usually conformed to the Church's practices. In Western Europe, Latin was the language of this education, and so there was a single language nearly all well educated people used over Western Europe. In Eastern Europe, Greek was used, but the Eastern Churches tended to use the vernacular more. Pilgrimage and crusades sometimes threw people of different countries together.
In western Europe it was Catholicism. When the whole of this area was converted to Catholicism it was itself as Christendom.
The Unifying Force has 544 pages.
military
in what way was Christianity a unifying force in the roman