Venerabile Arciconfraternita della Misericordia di Firenze (abbreviated Ven. Arc. Misericordia di Florence) is a lay confraternity founded in Florence in the 13th century by St. Peter Martyr with the aim of working towards the needy gestures of evangelical mercy. It is today the oldest Brotherhood for the care of the sick and, in general, the oldest private voluntary institution in the world still active since its foundation, dated in 1244 according to the records kept in its archive. Its lay members, called brothers, still continue to provide part of the infirm transport service in the city, and until April 2006 still wore the traditional black dress (dating back to the seventeenth century), today reduced to use in representation ceremonies due to national regulations inspired by road safety.
The Venerabile Arciconfraternita della Misericordia of Florence was a member of the Compagnia delle Misericordie, a confederation founded by Misericordia di Firenze, Rifredi and Bivigliano. In 2014 she returned to the National Confederation of Misericordie d'Italia, leaving the Compagnia delle Misericordie.
The Confraternity, known to the Florentines simply as La Misericordia, has dedicated itself since the beginning of its history to the transport of the sick to the hospitals of the city, to the collection of alms for poor girls to marry, to the burial of the dead, and to other works of charity. The foundation is uncertain: according to a legend, it was the work of Piero by Luca Borsi, while in a register of the Archconfraternity dated 1361 it is reported that the Confraternity was "begun for the blessed Messer Santo Pietro Martire of the Order of Preachers". It was, in particular, a filiation of the Societas Fidei established in 1244, with the name of Compagnia di Santa Maria della Misericordia.
The Confraternity quickly distinguished itself above all by its constant activity in the transportation of the sick and the burial of the dead, especially during the frequent pestilences. In a short time grew in numbers and popularity, as well as inevitably wealth, as they began to receive donations and bequests.
In the fourteenth century the Confraternity was recognized by the commune as a real public institution in a provision of March 31, 1329 which gave the Brothers the right to elect their leaders (capitan). Grand Duke Peter Leopold, who was a member, protected it during the suppression of the religious associations in 1784.