One issue with the study of the Middle Ages, is the very name of the time period. It postulates a middle ground that implicitly references the two endpoints - the Roman Empire and the so-called ‘Renaissance’. Like the middle child, the Middle Ages gets overlooked because of the name.
Casting about for a new name, I’ve considered two. The first is the Archipelago Ages. ‘Archipelago’ is used to emphasize how each city, village and county was its own little island in both space and time. The name accentuates how individuals study individual islands also highlights the differences and variety of each region. Researchers can also point out how a variety of sources changes how much we know about each island, labeling some islands as unknown due to the paucity of materials - with the unstated challenge that some future historian might some day explore the territory, adding to our knowledge.
Of course, most places are not literally islands, so we can postulate each island is connected via metaphorical ocean currents that allow for trade of culture and technology. Additionally, a tribe or group of people would colonize groupings of islands, thus describing similarities. Islands existing in contact -either geographically or on trade routes - would show similarities with their neighbors as well.
At least two objections to this name come to mind. First, although Europe does possess important islands- Britain, Ireland, Sicily and so on- peninsula is the major geographic feature, not island. Even more importantly, the image of historians studying a metaphorical archipelago holds for many time periods of history, not least of which would be the actual archipelagos of the Pacific and Indian Oceans. Archipelago Ages has distinct disadvantages and doesn't fit.
Concordat Era is the second and more fitting description of the Middle Ages. The one thing that seems common is people, both individually and in groups, were constantly making pacts and promises. Whether between lord and knight, town and king, or guild and artisan, contracts were everywhere. Even peasants made contracts - eg wealthy peasants contracted with poor to provide housing and clothing in exchange for household services. Even parents would contract with children to spell out exactly how much support the children had to provide after the parents retired.
By emphasizing the contracts the various issues of certain other words- eg the f-word-ism-are avoided. We sidestep whether the pacts were for land, money, goods, included juridical powers or military service. The compacts could be implicit by custom or explicit and spelled out in detail. In fact maybe that’s how historians should describe the cultures of the concordat era- the movement of implicit to explicit and back.
Since people like to use things they are familiar with, they would use familiar kinds of concordats, changing them to new conditions as needed. In this scheme, the Crusaders weren’t introducing a particular -ism, but simply taking up the tool they knew, adapting it as necessary and employing this tool for a goal - governance of the land conquered in the Crusades. Same thing for William the Conqueror after Hastings.
Concordat Era gives the Middle Ages new stature, as existing as more than a waypoint between ‘Antiquity’ and the ‘Modern’ era. The new name underscores the primary feature of the time period, including the variability and diversity, without the need for constant hedging about and equivocating. It gives the layperson a handle on what was going on for hundreds of years without extensive study of all cultures in Europe. Let’s start using it today.