In others, notably the United Kingdom, which lack a single overarching constitutional document, unwritten conventions are still of vital importance in understanding how the state functions.
For example the constitution of the Roman Republic was codified comparatively late in its development and relied for its functioning on traditions and a shared moral code called mos maiorum.
In the Holy Roman Empire such important issues as who could elect the emperor were entirely uncodified before the Golden Bull of 1356 and remained subject to a certain degree of interpretation well afterwards.
The other set of rules consist of conventions, understandings, habits, or practices that—though they may regulate the conduct of the several members of the sovereign power, the Ministry, or other officials—are not really laws, since they are not enforced by the courts.
[1]A century later, Canadian scholar Peter Hogg wrote: Conventions are rules of the constitution which are not enforced by the law courts.
For example, the constitutional convention that the Prime Minister of the United Kingdom cannot remain in office without the support of a majority of members of the House of Commons is derived from an unsuccessful attempt by the ministry of Robert Peel to govern without the support of a majority in the House, in 1834–1835.
"[3] More precisely, the conventions make certain acts, which would be permissible under a straightforward reading of the law, impermissible in practice.
There are several times when these conventions have been broken and an election has been held several months earlier: Because of the 1814 written constitution's pivotal role in providing independence and establishing democracy in the 19th century, the Norwegian parliament has been very reluctant to change it.
The two most important examples of constitutional conventions in the Norwegian political system are parliamentarism and the declining power of the King.
Mostly, they aim to reconcile the democratic principle of majority rule with the need to achieve consensus in a nation that is much more heterogeneous in many respects than other nation-states.
They are rules that are observed by the various constituted parts though they are not written in any document having legal authority; there are often underlying enforcing principles that are themselves not formal and codified.