Sejm of the Polish–Lithuanian Commonwealth

Until the end of the 16th century, unanimity was not required and majority voting predominated.[17][18] Later, with the rise of the magnates' power, the unanimity principle was enforced with the szlachta privilege of liberum veto (from the Latin: "I freely forbid").[19] From the second half of the 17th century, the liberum veto was used to paralyze sejm proceedings and brought the Commonwealth to the brink of collapse.[18][20] The growing power of sejmiks also contributed to the inefficiency of the sejm, as binding instructions from sejmiks could prevent some deputies from being able to support certain provisions.[18][21] The pro-majority-voting party almost disappeared in the 17th century, and majority voting was preserved only at confederated sejms (sejm rokoszowy, konny, konfederacyjny).[17] The liberum veto was finally abolished by the Constitution of May 3, 1791.[22]

Reforms of 1764–66 improved the proceedings the sejm.[23] They introduced majority voting for items declared as "non crucial" (most economic and tax matters) and outlawed binding instructions from sejmiks.[23] Reforms of 1767 and 1773–75 transferred some competences of the sejm to the commissions of elected delegates.[23] From 1768, hetmans were included among the senate members, and from 1775 also the Court Deputy Treasurer.[23]

In the senate there was no voting; after all the senators who wished had spoken on a given matter, the king or the chancellor formed a general opinion based on the majority.[18]

The Constitution of May 3, 1791 finally abolished the liberum veto, replacing it by majority voting, in most important matters requiring 75% of the votes.[16]

Seating chart of the Senate

The sejm comprised two chambers, with varying numbers of deputies. After the 1569 Union of Lublin, the Kingdom of Poland was transformed into the federation of the Polish–Lithuanian Commonwealth and the numbers of sejm participants were significantly increased with the inclusion of the deputies from Lithuanian sejmiks.[24] The deputies had no set term of office, although in practice it was about four months long, from their election at a regional sejmik, to their report on the next sejmik dedicated to hearing and discussing the previous sejm's proceedings (those sejmiks were known as relational or debriefing).[17] Deputies had parliamentary immunity and any crimes against them were classified as lèse-majesté.[17]

The two chambers were:

• The senate (senat) consisting of high ecclesiastical and secular officials; it was an evolution of the royal council. The senate numbered over 140 bishops and Senatorial offices of the Polish–Lithuanian Commonwealth;[25] it grew from 149 around 1598–1633 to 153 around 1764–1768, and 157 during the era of the Great Sejm (1788–92).[26] The Constitution of May 3 set their number at 132.[16]
• The lower house, Chamber of Deputies (izba poselska), the sejm proper, of lower ranking officials and general nobility.[11] In the Polish–Lithuanian Commonwealth, the number of lower house deputies exceeded that of the senators.[26] In 1569 it was composed of 170 deputies representing and elected by a local sejmiks. The 170 included 48 from Lithuania.[27] Deputies from several cities and towns were allowed a status of observers.[27] The number of deputies grew to around 236 in 1764–68, dropping to 181 during the time of the Great Sejm (1788–92).[26] The Constitution of May 3 set their number at 204, including 24 non-voting representatives from cities and towns.[16]

The Constitution of May 3 specified that the deputies were elected for two years, and did not require reelection in that period if any extraordinary sejms were to be called.[16] Senators, for the most part, were selected by the king from a number of candidates presented by the sejmiks.[16]

Due to population size differences between Lithuania and Poland, the Grand Duchy had three times less representatives than the Crown.[28] Usually larger voivodeships could send 6 deputies, smaller 2; ziemias, depending on their sizes, would send 2 or 1.[27] Numbers of deputies elected to the sejm by sejmiks from particular localities, in the order of precedence, based on a 1569 decree, were as follows:[29][30]

A sejm began with a solemn mass, a verification of deputies mandates, and election of the Marshal of the Sejm (also known as the Speaker).[31][32] (The position of the Marshal of the Sejm (and sejmik) who presided over the proceedings and was elected from the body of deputies evolved in the 17th century.[11]) Next, the kanclerz (chancellor) declared the king's intentions to both chambers, who would then debate separately till the ending ceremonies.[32]

After 1543 the resolutions were written in Polish rather than Latin.[33] All legislation adopted by a given sejm formed a whole and was published as a "constitution" of the sejm. Prior to the May 3 Constitution, in Poland the term "constitution" (Polish: konstytucja) had denoted all the legislation, of whatever character, that had been passed at a sejm.[34] Only with the adoption of the May 3 Constitution did konstytucja assume its modern sense of a fundamental document of governance.[35] From the end of the 16th century, the constitutions were printed, stamped with the royal seal, and sent to the chancelleries of the municipal councils of all voivodeships of the Crown and also to the Grand Duchy of Lithuania.[18][36] Such constitutions were often subjected to some final tweaking by the royal court before being printed, although that could lead to protests among the nobility.[18]

Old and New Chamber of Deputies at the Royal Castle, Warsaw

The majority of the sejms were held at the Warsaw's Royal Castle.[24] A few were held elsewhere, particularly in the first years of the Commonwealth, and from 1673, every third sejm was to take place at Grodno in the Grand Duchy of Lithuania (first hosted in the Old Hrodna Castle, later in the New Hrodna Castle).[25] In practice, most of the sejms were still held in Warsaw, which hosted 148 sejms, compared to 11 sejms hosted in Grodno.[37]

The sejms in Warsaw were held in the Warsaw Castle, within the Chamber of Deputies (Hall of Three Pillars), with the upper Senate Chamber located literally above it.[37] In the late 17th century, new quarters were constructed for the Chamber of Deputies, and were joined on the same level by the senate quarters in the mid-18th century.[37] The new Senate Chamber was the larger of the two, as it was intended to host both chambers during the opening and closing ceremonies.[37]

In the mid-15th century the general sejm of the Kingdom of Poland met about once per year.[11] There was no set time span to elapse before the next session was to be called by the king.[13] If the general sejm did not happen, local sejmiks would debate on current issues instead.[11]

King Henry's Articles, signed by each king since 1573, required the king to call a general sejm (lasting six weeks) every two years, and provisions for an extraordinary sejm (Polish: sejm ekstraordynaryjny, nadzwyczajny) that was to last two weeks were also set down in this act.[17][25] Extraordinary sejms could be called in times of national emergency, for example a sejm deciding whether to call pospolite ruszenie (a general call to arms) in response to an invasion. The sejm could be extended if all the deputies agreed.[25] No set time of a year was defined, but customarily sejms were called for a time that would not interfere with the supervision of agriculture, which formed the livelihood of most nobility; thus most sejms took place in late fall or early winter.[17]

After the Constitution of May 3, 1791, sejms were to be held every two years and last 70 days, with a provision for an extension to 100 days.[16] Provisions for extraordinary sejms were made, as well as for a special constitutional sejm, which was to meet and discuss whether any revisions to the constitution were needed (that one was to deliberate every 25 years).[16]

It is estimated that between 1493 and 1793 sejms were held 240 times.[38] Jędruch gives a higher number of 245, and notes that 192 of those were successfully completed, passing legislation.[17] 32 sejms were vetoed with the infamous liberum veto, particularly in the first half of the 18th century.[17] The last two sejms of the Commonwealth were the irregular four-year Great Sejm (1788–92), which passed the Constitution of the 3 May, and the infamous Grodno Sejm (1793) where deputies, bribed or coerced by the Russian Empire following the Commonwealth defeat in the War in Defense of the Constitution, annulled the short-lived Constitution and passed the act of Second Partition of Poland.[39][40]

Election of Stanisław August Poniatowski in 1764 (detail)

In addition to the regular sessions of the general sejm, three special types of sejms handled the process of the royal election in the interregnum period.[41] Those were:

• Convocation sejm (Sejm konwokacyjny). This sejm was called upon a death or abdication of a king by the Primate of Poland.[41] The deputies would focus on establishing the dates and any special rules for the election (in particular, preparation of pacta conventa, bills of nobility privileges to be sworn by the king), and screening the candidates.[41] This sejm was to last two weeks.[17]
• Election sejm (Sejm elekcyjny), during which the nobility voted for the candidate to the throne. This type of sejm was open to all members of the nobility who desired to attend it, and as such they often gathered much larger number of attendees than the regular sejms.[41][42] The exact numbers of attendees have never been recorded, and are estimated to vary from 10,000 to over 100,000; subsequently the voting could last for days (in 1573 it was recorded that it took four days).[43] To handle the increased numbers, those sejms would be held in Wola, then a village near Warsaw.[41] Royal candidates themselves were barred from attending this sejm, but were allowed to send representatives.[43] This sejm was to last six weeks.[17]
• Coronation sejm (Sejm koronacyjny). This sejm was held in Kraków, where the coronation ceremony was traditionally held by the primate, who relinquished his powers to the chosen king.[44] This sejm was to last two weeks.[17]

The Constitution of May 3, 1791 is adopted by the Four-Year Sejm and Senate at the Royal Castle, Warsaw

Confederated sejm (Sejm skonfederowany) first appeared in 1573 (all convocation and election sejms were confederated), and became more popular in the 18th century as a counter to the disruption of liberum veto.[45] Seen as emergency or extraordinary sessions, they relied on majority voting to speed up the discussions and ensure a legislative outcome.[17][45] Many royal election sejms were confederated, as well as some of the normal sejm walny (general sejm) sessions.[41][45]

Jędruch, who classifies the regular general sejm session as ordinary, in addition to the convocation, election and coronation sessions, also distinguished the following additional types:

• Council of state
• Constitutional
• Delegation (ending with a formation of committees)
• Extraordinary
• General sejmik held instead of a sejm
• General council (rada walna) without the king present. That sejm would be convoked by the primate when the king could not attend and had no legislative powers. It was attended by deputies from the preceding sejm. Held three times (in 1576, 1710 and 1734).
• Inquest, debating the case of royal impeachment. Two such sejms were held (in 1592 and 1646).
• Pacification, to quell a potential civil war after a disputed election, to pacify the opponents through political concessions. Five such sejms were held (in 1598, 1673, 1698, 1699 and 1735).[7][17]