In 594 BC, Solon, the ruler of Athens, created the new Solonian Constitution.It eased the burden of the workers, and determined that membership of the ruling class was to be based on wealth (plutocracy), rather than on birth (aristocracy).Some constitutions (such as the constitution of the United Kingdom) are uncodified, but written in numerous fundamental Acts of a legislature, court cases or treaties.
Sometimes the problem is not that a statute is unconstitutional, but that the application of it is, on a particular occasion, and a court may decide that while there are ways it could be applied that are constitutional, that instance was not allowed or legitimate.
In such a case, only that application may be ruled unconstitutional.
A constitution is an aggregate of fundamental principles or established precedents that constitute the legal basis of a polity, organisation or other type of entity, and commonly determine how that entity is to be governed.
When these principles are written down into a single document or set of legal documents, those documents may be said to embody a written constitution; if they are written down in a single comprehensive document, it is said to embody a codified constitution.
The Romans first codified their constitution in 450 BC as the Twelve Tables.
They operated under a series of laws that were added from time to time, but Roman law was not reorganised into a single code until the Codex Theodosianus (AD 438); later, in the Eastern Empire, the Codex repetitæ prælectionis (534) was highly influential throughout Europe.
In this context, "within power", intra vires, "authorized" and "valid" have the same meaning; as do "beyond power", ultra vires, "not authorized" and "invalid".
In most but not all modern states the constitution has supremacy over ordinary statutory law (see Uncodified constitution below); in such states when an official act is unconstitutional, i.e.
Action that appears to be beyond power may be judicially reviewed and, if found to be beyond power, must cease.
Legislation that is found to be beyond power will be "invalid" and of no force; this applies to primary legislation, requiring constitutional authorization, and secondary legislation, ordinarily requiring statutory authorization.