The Articles were a collection of legal provisions that included paramount regulation of the structure of the state and determined the relations between the Sejm and the monarch. The Articles guaranteed that the privileges of the gentry (szlachta) would be preserved, ensured freedom of religion, and defined the constitutional framework of the Rzeczpospolita, including the choice of every subsequent monarch by the gentry as a whole, exclusively via free election. The Henrician Articles bound the king to convene a general Sejm every two years and, when need be, extraordinary Sejms as well. The king was also obliged to appoint a royal council composed of sixteen resident senators tasked with making joint decisions concerning major affairs of state. Legislative powers rested with the Sejm, which also enjoyed purview over both domestic and foreign policies. Moreover, the szlachta (gentry) gained the right to renounce allegiance to the king if ever the latter broke the obligations he had agreed to.

Some Polish legal historians are inclined to treat the Henrician Articles as the first act of a constitutional character.

The signatories of the ceremonious document – affixed, as seen below, with numerous seals – regulated the most urgent matters. One of them is dealt with in points 3 and 4 – namely, the guarantee to uphold peace between the adherents of the diverse confessions then practised in the Rzeczpospolita (Commonwealth) The signatories mutually swore to oppose any and all attempts to initiate persecutions for reasons of religion. At the same time it was stressed that religious matters could not be used as a pretext for undermining the social order.

Of surpassing significance for the origins of the provisions upholding religious freedom was the fact that among the leading candidates to the vacant throne was the son of the French king, Henry (de Valois) who had been charged with having directly participated in the slaughter of French Protestants (Huguenots) during the St. Bartholomew’s Day Massacre of August 23-24, 1572 in Paris. In accordance with the stipulations of the Warsaw Confederation, when Henry indeed was elected to the throne of the Rzeczpospolita (in May, 1573), the Polish delegation that traveled to France demanded of the king-elect that he swear an oath to uphold the principles of the Warsaw Confederation. Henry did so in Notre Dame Cathedral in September that year.

The fact that freedom of religion was made part of the Henrician Articles attests that the provisions of the Warsaw Confederation were to remain binding indefinitely, rather than only during the interregnum and Henry’s reign.

From January 1569, the Polish and Lithuanian parliaments (sejms) held their debates in parallel, bargaining for a union agreement. The deliberations were acrimonious, but eventually led to the signing, in Lublin, of an act of real union between the Crown and the Grand Duchy of Lithuania. This happened on July 1, 1569.

The Union of Lublin provided for the merger of the two sovereign countries, Poland and Lithuania, into a single unit that became called ‘the Commonwealth [Rzeczpospolita] of the Two Nations’, to be ruled by a single monarch elected jointly by the two nations in free elections. The Rzeczpospolita was henceforth to have a joint Sejm (parliament) and a shared foreign policy. The central offices specific to each of the countries were preserved, as were their respective official languages, armies, treasuries, and judicial systems. A single currency was also introduced – however, it was minted separately in each of the two countries.

Nihil novi rendered the “Union of Mielnik” null-and-void in its entirety and strictly limited the legislative competences of the monarch and the Senate, banning the issuance of laws without the consent of the senators and gentrymen represented in the Chamber of Deputies. The thrust of Nihil novi was essentially to reinforce the position of the bicameral parliament in the political system of the Polish-Lithuanian Rzeczpospolita (Commonwealth). In so doing, the parliament, and particularly its Chamber of Deputies, attained the position of highest authority in the state. The functioning of the Sejm was henceforth to be based on smooth co-operation between the king, the royal council – i.e. the Senate – and the deputies elected locally or regionally to the Chamber of Deputies.

Constitutional and legal historians recognize Nihil novi as marking the beginning of the ‘nobles’ democracy’ (or, democracy of the nobility) in the Polish-Lithuanian Rzeczpospolita.

The central provision of the document was its consent to a thorough-going alliance between the Crown and the Grand Duchy. The joint election of the monarch – the king of Poland, to be sure – was envisioned, this implying that the Jagiellons would lose their right to inherit power in Lithuania. At his coronation, every subsequent king was to re-affirm all the existing rights of the Kingdom of Poland and the Grand Duchy of Lithuania. A jointly appointed council was meant to deliberate on the state’s affairs.

In the end, the Lithuanian side never ratified the Union of Mielnik. Nonetheless, the Privilege is regarded as the first step towards the union that was finally forged between Poland and Lithuania in 1569.