What kind of government did Europe have in the 1400s?

Europe has never had one government. Europe is a conintent made up of many countries, each with their own governments of varying types.

In the 1400s the modern concept of the nation state had not yet developed.

The 1400s were the feudal period in Europe. Most governments were feudal monarchies. This was a multi-layered system of government by hereditary rulers. A king did not have absolute rule, but the had 'allegiance' of lower level nobles who paid him 'dues' (taxes) and provided soldiers if needed. These feudal layers overlapped and changed, so an area could change from being a feudal subject of in one country, to being independent, to being part of Another Country without changing its local feudal lord.

There were also a number of republics. These were mostly in what is now Italy (examples: Florence, Venice). In most cases the vote was hereditary and only a minority of the population had a vote.

In the east some of the kingdoms were still of a tribal nature, feudalism not having developed yet.