Conclave (Lat. Cum With And Clanis, Key), the apartments where the cardinals of the Roman Catholic church assemble for the election of a new pope, or the assembly of cardinals shut up for such election. Many reasons have led to the bestowing on the college of cardinals the exclusive right of electing the pope, as well as to the reclusion in which they are kept while exercising that right. During the era of persecution the position of bishop in Rome or elsewhere was one of great peril, for which none but the most eminent in virtue were likely to be chosen by the clergy and people. But already in the age of Constantine the play of human passions became frequently but too apparent both in the men who aspired to the episcopal office, and in those in whose gift it was. In proportion as the church increased in numbers, wealth, spiritual influence, and political power, so did the choice of men to fill such great sees as those of Rome, Constantinople, and others, become the occasion of most unseemly intrigue and strife. The emperors, from motives of policy, wished to have seated in the papal chair men who would subserve their own interests; and from first protecting the liberty of ecclesiastical elections, they soon came to oppress it.

Justinian claimed the right of confirming the choice of the Roman clergy and people, and this in practice meant the setting it aside. It was further maintained that Adrian I. had bestowed on Charlemagne the right of choosing the pope; but be that as it may, the German emperors constantly interfered in papal elections, causing thereby ever-recurring disorders, delays, divisions, and sometimes bloodshed. To protect the freedom of the electors, and to put a stop to these scandalous contentions, Nicholas II. in 1059 decreed that in future the election of the Roman pontiff and the administration of his see during the vacancy should be the exclusive right of the cardinals of the Roman church. After a violent struggle with the imperial power, these statutory dispositions triumphed through the energy of Gregory VII. In 1179 Alexander III. solemnly confirmed the decree of Nicholas, prescribing that a two-thirds vote should be necessary for a valid choice. Meanwhile no statute existed compelling the cardinals to reclusion while discharging their office of electors; but several instances are on record where such reclusion was resorted to with the most beneficial result. The election was thus made in perfect freedom from all outside violence and intrigue.

Hono-rius III. was elected two days after the death of his predecessor, in consequence of the strict reclusion to which the cardinals submitted; while Gregory X. was only chosen after a vacancy of two years and nine months, because the electors were not shut up. These two extreme cases induced Gregory in 1274, during the council of Lyons, to decree a strict reclusion thenceforward, with all the other conditions which have substantially continued dowm to the present day. After Gregory's death these statutes were repeatedly violated, until the evil thence resulting culminated at the death of Nicholas IV. in 1292, when Celestine V. was chosen after an interregnum of two years and three months. Celestine renewed before his abdication, with increased solemnity and rigor, the pontifical constitutions on the conclave, and had the satisfaction of seeing them carried out to the letter in the conclave which elected Boniface VIII. Boniface, in his turn, confirmed the constitution of Celestine by one of his own, and both were embodied by him in the 6th book of his Decretals. During the council of Trent this reclusion, which had become the uniform law of the church, was again the subject of the most severe and minute legislation by Pius IV. He regulated everything pertaining to the lodging of the cardinals in conclave, to their seclusion from all intercourse with the world outside, their diet, attendants, and the manner of voting.

Gregory XV. in 1621 decreed strict reclusion as an absolute condition for validity. Clement XII. in 1732 renewed and confirmed these disciplinary statutes, adding some new rules concerning the administration of the Roman see during its vacancy. - The whole ceremonial observed in the conclave may be thus briefly described from Patricius (Patrizzi) and modern authorities. Nine whole days are given to devotional exercises for the eternal repose of the deceased pontiff. On the ninth take place his obsequies, and on the tenth the cardinals assemble in the Sistine chapel, where a mass in honor of the Holy Ghost is celebrated by the cardinal dean. This over, the cardinal dean intones the Veni, Creator Spiritus, and the sacred college, with their officers and attendants, go in procession to that part of the Vatican set apart for their reclusion, immediately adjoining and including both the Sistine and Pauline chapels., with three courts and the surrounding apartments. On their arrival in the Pauline chapel, the cardinal dean chants before the altar the prayer Deus, qui corda Jidelium, and the papal constitutions on conclaves are read, all present swearing solemnly to observe them. Formerly it was the custom to begin from that moment the rigorous reclusion prescribed by the pontifical decrees.

In modern times it only commences on the evening of the tenth day. As soon, however, as the signal for the prescribed reclusion is given, all meet in the chapel, cardinals and conclavists (all the authorized officers and attendants in the conclave), the oath of fidelity and secrecy is administered to conclavists and guardians, and three cardinals (chosen one from each of the three orders of bishops, priests, and deacons), accompanied by the high chamberlain (camerlingo) and the first master of ceremonies, make a scrupulous examination of every room and corner from cellar to garret, in order to see that there are no intruders. The only door of communication having been then closed with two strong locks on the outside and two within, the conclave is formally begun. The cells in which the electors are locked up are simple in their construction and their furniture. They are draped in purple for the cardinals created by the last pope, and in green for all the others. The following daily routine is observed as long as the reclusion lasts. At 6 o'clock in the morning a master of ceremonies knocks at the door of each cell to warn the inmate to proceed to the chapel. At 7 the mass of the Holy Ghost is celebrated, after which all except the cardinals withdraw.

The cardinals recite the penitential psalms and the litany of the saints, and a first vote is cast. This over, the fathers retire to their cells, breakfast, and take a short walk in the open air. At 2 o'clock P. M. they again meet in the chapel for a second ballot, after which they dine, walk out if they choose, or retire to their respective cells, where a religious silence is observed after dark. Gregory XV. decreed that the cardinals in conclave should vote by secret ballot. Papers of uniform size, texture, and color are distributed to the cardinals; they are folded in such a manner that the part on which each elector writes his own name cannot be opened, while that on which he inscribes the name of his candidate can. The ticket is then folded, closed with sealing-wax, and stamped with the common seal of the conclave. The elector, then kneeling, takes the solemn oath prescribed, and deposits his vote in a chalice placed on the altar. The votes of such as are detained by sickness in their cells are taken with every necessary precaution and formality. "When all have voted, three cardinals, chosen one from each order in the sacred college, take the papers one by one from the chalice, read them aloud, and register them, each in succession.

As soon as a two-thirds vote is obtained, the fact is announced. The elect, if he accepts, immediately chooses the name by which he is to be known, and receives the first homage of all present. He is next clad in the vestments and insignia of his office, and receives homage a second time. Thereupon the first in the order of cardinal deacons, preceded by a cross-bearer, goes to a balcony in the Vatican and proclaims the name of the new pope.