A religious controversy in 1858 in Cork led to the opening of the Protestant Hall, later called the Assembly Rooms. The Committee of the Athenaeum, now the Opera House, refused permission for an ex-priest called Gavazzi to lecture there. The Committee disliked the anti-Catholic tone of Gavazzi's sermons. Many Protestants in the city were outraged at the refusal. Those attending a public meeting held in the Primitive Wesleyan Church on 17 December 1858 decided to build the Protestant Hall for the use of all citizens of Cork. The Earl of Bandon laid the foundation stone in 1860 and opened the hall on 12 April 1861. The entrance to the hall was not completed until 1869.
Richard Rolt Brash designed the building. Brash was a distinguished antiquarian as well as an architect. He published articles in many learned journals. His major work is the The ogam inscribed monuments of the Gaedhil in the British islands which was published in 1879 after his death. He died at his house in Sunday's Well on 18 Jan 1876 and is buried in St Finbarr's Cemetery.
Many events were held in the Hall over the years including operas and a boxing match involving the well-known Cork fighter Pakie Mahony. The Assembly Rooms was the first place in Cork where moving pictures were shown in 1896. It was a cinema from the early 1900s until 1964 and had the reputation of being a flea pit. The best-known member of the staff at the cinema was the usher George O'Sullivan. Members of the audience would shout 'Georgie, remove the body' whenever anyone died on screen.
The Capuchin order bought the hall after it closed as a cinema. The interior of the hall was gutted in 1970. The exterior survives unchanged except for the name over the entrance.
Boys from the St. Francis Training Centre for young people with problems, run by the Capuchins, opened a coffee shop there in 1989. Later it became a restaurant called The Assembs.
Threshold, the National Housing Agency, took over the premises in 2005.