What two european countries finally united under one ruler as a result of nationalistic feelings?

The answer is Austria and Hungary.

The subsequent country was known as the Austro-Hungarian Empire. It was a powerful state that existed between 1867-1918 when it disintegrated after defeat in World War I.

For more than half a century, the Empire was a powerful state in European and global affairs.

Interestingly it also had two capitals, Vienna and Budapest, both of which became the capitals of Modern Austria and Hungary.

He would most likely post his laws in the city market