LACEDONIA, DIocese of. – A city and diocese in the province of Avellino. It has 35,948 inhabitants, of whom 34,673 are Catholics, distributed across 11 parishes served by 29 diocesan priests and 2 regular clergy; it has a seminary, one male religious community, and six female communities (1950). The diocese is a suffragan of Conza. Its patron is St. Nicholas of Bari (feast day: December 6).
According to some, the city arose on the ruins of the ancient Aquilonia of the Hirpini. The Vulture earthquake of 1456 destroyed much of it, and severe damage was caused to the buildings by the earthquake of July 1930. In the Cathedral, dedicated to the Assumption, the famous "Barons' Conspiracy" against Ferdinand I of Aragon was sworn on the night of September 10–11, 1486.
The suppressed see of Trevico (Vico della Baronia) was united to the diocese of Lacedonia in 1818.
Among its bishops are remembered Angelo, who took part in the Third Lateran Council (1179); Fra Guglielmo Neritono (1392), Antonio Dura (1506), Giacomo Candido (1606), Giacomo Giordano, who built the episcopal palace; and Morea, who in 1684 suppressed some paganizing customs on the eve of Epiphany.