The Constitution of May 3, 1791 is generally regarded as Europe's first and the world's second modern codified national constitution, following the 1788 ratification of the United States Constitution. The May 3, 1791, Constitution was adopted as a "Government Act" on that date by the Sejm (parliament) of the Polish–Lithuanian Commonwealth. It was in effect for only a year, until the Russo-Polish War of 1792.

Labour Day or Labor Day is an annual holiday celebrated all over the world that resulted from the labor union movement, to celebrate the economic and social achievements of workers. The majority of countries celebrate Labor Day on May 1, and it is popularly known as May Day and International Workers' Day, while some celebrate on the first Monday of September.

The celebration of Labor Day has its origins in the Eight-hour day movement, which advocated eight hours for work, eight hours for recreation, and eight hours for rest.