A parliamentary system may be either bicameral, with two chambers of parliament (or houses) or unicameral, with just one parliamentary chamber.A bicameral parliament usually consists of a directly elected lower house with the power to determine the executive government, and an upper house which may be appointed or elected through a different mechanism from the lower house.
A parliamentary system of government means that the executive branch of government has the direct or indirect support of the parliament. This support is usually shown by a vote of confidence. A balanced relationship between the executive and the legislature in a parliamentary system is called responsible government .
In 930, the first assembly of the Alþingi was convened at Þingvellir in Iceland, becoming the earliest version of a formalized parliamentary system. It was a combination of national assembly, court of justice and yearly cerebration, where the most powerful leaders, called goðar, met to decide on legislation and dispense justice, with the whole community in attendance.
In a parliamentary system, the legislature is the part of government that makes laws. The legislature also gives power to the executive (the part of government that enforces laws). This is the basic form of a parliamentary republic. The difference is how the legislature gets its power. The legislature is not chosen by a ruler or by birth.
Typically, parliamentary republics are states that were previously constitutional monarchies with a parliamentary system, with the position of head of state given to a monarch.  Following the defeat of Napoleon III in the Franco-Prussian War , France once again became a republic – the French Third Republic – in 1870.