The national flag of Poland (flaga Polski [ˈfla.ɡa ˈpɔl.ski]) consists of two horizontal stripes of equal width, the upper one white and the lower one red.

A variant of the flag with the national coat of arms in the middle of the white fess is legally reserved for official use abroad and at sea.

White and red were officially adopted as national colours in 1831, although these were associated with Poland since the Middle Ages and were emphasized on royal banners.

Horizontal bicolours of white and red being a relatively widespread design, several flags are similar but unrelated to the Polish one.

[2] Public disrespect, destruction or intentional removal of the flag is considered a crime punishable by a fine, penal servitude or up to one year of imprisonment.

[6] According to the Coat of Arms Act, everyone can use the Polish flag, especially during national and cultural events, as long as it is done in a respectful manner.

That is why the Polish flag, as a symbol of patriotism and resistance against the Communist rule, is part of the Solidarity trade union logo.

[3] The variant with the coat of arms, even though its incorrect usage, is often used by the Polonia, or Polish diaspora outside Poland, especially in the United States.

[9] State and local government organs are legally required, and other institutions and organisations as well as all citizens are encouraged to fly the Polish flag on the following days: The flag is often popularly flown during important sporting events, such as the FIFA World Cup, if Polish athletes are participating;[10] and during an official visit of a particularly important person, especially a pope, in Poland.

Multiple flags, on the other hand, are normally used to decorate both public and private buildings to mark special occasions, such as national holidays.

If the flag is hung vertically above a street, the white stripe should be placed on the left when looking in the direction of increasing house numbers.

It should be also secured from being torn off or falling to the ground and it should not be flown outdoors during a heavy rain, blizzard or very strong wind.

When no longer in a fit condition to be used, it should be disposed of in a dignified manner, preferably by cutting it in half so as to separate the colours and then, burning.

[3] The earliest vexilloids (flag-like objects) used in Poland were known as stanice and probably resembled the Roman vexillum, that is a cloth draped vertically from a horizontal crosspiece attached to a wooden pole or spear.

The royal banner of arms dates back to the reign of King Boleslaus the Generous (r. 1076–1079), but it was during the reign of King Ladislaus the Short (r. 1320–1333) that a red cloth emblazoned with the White Eagle of the arms of Poland was finally established as the Banner of the Kingdom of Poland, a symbol of royal authority used at coronations and in battles.

Since both Polish and Lithuanian coats of arms consisted of white (Argent) charges in a red (Gules) field, these two colours started to be used for the entire banner.

During that time, the cockade worn by the Polish military had, like in Saxony, the form of a white silk ribbon with a knot in the middle.

White and red were first publicly used as national colours by civilians on 3 May 1792 in Warsaw, during a celebration of the first anniversary of the adoption of the Constitution of 1791.

On 7 February 1831 it adopted white and red, the tinctures (colours) of the Polish and Lithuanian coats of arms, as the national cockade of Poland.

White and red colours were also used by civilians to show their protest against the Russian rule, as well as by people in France, Britain, Germany, Belgium and other countries as a sign of their sympathy with the Polish cause.

Left-wing politicians of the time, such as Joachim Lelewel, continued to regard the revolutionary blue, white and red as true national colours.

On 1 August 1919, almost a year after Poland regained independence in November 1918, the Sejm officially introduced a white-and-red bicolour as the Polish national flag.

[13] Apart from changes in the legal specifications of the shades of the national colours (see the section below), the basic design of the Polish flag, including the 5:8 ratio, has remained unchanged to this day.

20th-century Polish insurgents wore white-and-red brassards (armbands) which played a role similar to the cockade of previous centuries.

A royal ban on wearing this colour could be a form of punishment; in the 14th century, the Nałęcz clan of Greater Poland were forbidden to dress in crimson for their ancestors' complicity in the assassination of King Premislaus in 1296.

[13] In the first half of the 19th century, due to the influence of French fashion, crimson was largely replaced with the cheaper amaranth.

In 1921, the Ministry of Military Affairs issued a pamphlet with illustrations of the Polish flag and other national symbols which used the crimson shade of red.

[13] The Coat of Arms Act of 31 January 1980[2] replaced the verbal prescription with trichromatic coordinates in the CIE colour space as proposed by Nikodem Sobczak, an expert in colorimetry,[17] bringing the resulting hue closer to crimson again.

The flag of the Grand Duchy of Posen, a Polish-populated autonomous province of the Kingdom of Prussia created in 1815, was a red-and-white horizontal bicolour.

With Germany's increasingly anti-Polish policy and a rising identification of white and red as Polish national colours, the red-and-white flag of Posen was replaced in 1886 with a white-black-white horizontal triband.