A constitution is a set of basic rules, regulations and principles according to which a government governs its states and cities. A written constitution is one in which all the precedents and regulations are written down on a single document whereas there are some countries which do not have written constitutions but oral principles which its people have to abide by.
The idea of a constitution is very old and has been going on in the world from a very long time. Some of these old constitutions are still being followed by certain countries with some changes which have been made over a period of time.
San Marino is the country which has the oldest known national constitution in the world. It was formed on October 8, 1600.
The constitution of United States is also one of the oldest in the world as it was formed in the year 1788. Norway is yet another country whose constitution was made long back in the year 1814.
Some other countries whose constitutions were made decades back area Netherlands whose constitution was made in 1815, Belgium whose constitution was made in 1831, Argentina whose constitution was made in 1853, Tunisia whose constitution was made in 1861 and Canada and Luxembourg.