What are the similarities and differences between a monarchy and a dictatorship?

Both the monarchy and the dictatorship are systems of government with one person as ruler, but they differ in some important particularities.

Historically, a monarch was the single most powerful individual in a state, and generally whatever they said was law. This has changed much in the modern period, and most present-day states which have a monarch actually govern through a parliament or similar body. In a dictatorship, all of the power in the state is definitely concentrated in the hands of the dictator.

Under a constitutional monarchy (as in the United Kingdom) the monarch is limited in their power by a written constitution. Typically, a parliament is also in place to govern the state without putting too much power in one person. The constitutional monarchy helps to protect the people from being taken advantage of by the monarch. In contrast, a dictatorship has no constitutional limitations, and even if there is a constitution in place, the dictator may be free to make changes to it at any time.