Final answer:
Denmark was unified and Christianized by Harald I in 965 and became a constitutional monarchy in 1849. Harald Bluetooth played a key role in this transformation, marking a vital moment in Dan-ish history. Denmark's shift mirrored broader European developments from absolute to constitutional monarchies.
Step-by-step explanation:
The country unified and Christianized by Harald I in 965 was Denmark. Renowned for his role in the conversion and unification of Denmark, Harald I, also known as Harald Bluetooth, is considered a pivotal figure in Dan-ish history. This transformation is commemorated by the Jelling Stone, often referred to as Denmark's 'baptismal certificate.' The shift toward Christianity reflected the broader European trend of monarchies defending and promoting Christianity as the foundation of their rule during the Middle Ages.
In 1849, Denmark transitioned into a constitutional monarchy, a system in which the powers of the monarch are restricted and regulated by a constitution, which also embodies the political and legal institutions of the country. This change was part of a larger movement occurring across Europe, where the ideas of absolute monarchy were making way for constitutional systems that shared power between rulers and their subjects.