As recent tree-ring dating has proved, the present Hall was built at some time between 16.But some of the timbers used in its construction are older than the building, dating from the mid-16th century: they may well have been recycled from an earlier market hall which is known to have existed in Llanidloes.
Religious groups including Quakers, Baptists, Independents and Methodists used it for meetings, and John Wesley preached here several times; in 1749 addressing a large congregation from the "Wesley Stone" now outside the north-west corner.
Originally known as "the Booth Hall" from the market stalls or "booths" which stood beneath and around it, the hall was the focus of Llanidloes markets until the early 20th century.
Its upper storey also played many other parts during its long career.
His most recent book is Quaternary Dating Methods, (John Wiley, Chichester & New York, 2005).
He has published more than 140 scientific papers and other contributions, and is co-author of two Quaternary textbooks: Reconstructing Quaternary Environments (with John Lowe), (1st edition, Longman, 1984; 2nd edition, Addison-Wesley-Longman, 1997), and Late Quaternary Environmental Change: Physical and Human Perspectives (with Martin Bell), (1st edition, Longman, 1992; 2nd edition, Pearson International, 2005). Formal subdivision of the Holocene Series/ Epoch: a Discussion Paper by a Working Group of INTIMATE (Integration of ice-core marine and terrestrial records) and the Subcommission on Quaternary Stratigraphy (International Commission on Stratigraphy).