What features did medieval civilization inherit from barbarism and antiquity?

We are talking about the period from the 5th to the 15th century, the following features can be distinguished:

Latin. After the fall of the Roman Empire, it became an international language, it was studied by all at least relatively educated people, even in the 17th century (the Slavic-Greek-Latin Academy in Moscow).
The Pope has been in office since the 4th-5th centuries. Like the patriarch in Constantinople, they also influenced the religious affairs of the Middle Ages.
Christianity. It became the main religion of the Roman Empire around 330.
Trade routes. They were laid by the Romans, in the V-XIV centuries nothing fundamentally new was discovered, only in the middle of the 15th century the Portuguese sailed to Senegal, and by the end of the century to India.
From the era of barbarism, they inherited cruelty.
Monarchy. In the Middle Ages, as in Rome, almost all states were ruled by kings and emperors, there were dynasties. Other forms of government (a republic in Venice, veche republics in Novgorod and Pskov) were rare.