Blandford Forum developed as one of the major market towns in the eastern part of Dorset during the later medieval period. The main reason for its development was that the main roads from Salisbury to Dorchester and from Poole to Shaftesbury met there to cross the River Stour.
The growing significance of the town was recognised in 1605 when it was formally incorporated as a borough with its own portreeve (or mayor) and burgesses. The town was one of the polling places for county elections and was also home to the Bishop of Bristol's registry for the archdeaconry of Dorset until the county was transferred to the diocese of Salisbury in 1836.
In 1713 and again in 1731, the town was destroyed by fire. The first blaze decimated much of the eastern part of the town. The second and more serious destroyed virtually everything that had survived the first fire so that the only buildings remaining today that predate these two catastrophes are the Old House c.1660 in The Close, and the Ryves Almshouses c.1682 in Salisbury Street.
After the fire of 1731 the town as rebuilt according to the earlier street pattern except that the central part of the market place was left as open space. Today Blandford Forum is one of the best preserved Georgian market towns in England. The majority of the buildings in the centre of the town date from the period 1735-1760.
The Bastard brothers, John and William, local architects, entrepreneurs and politicians, were responsible for the rebuilding programme. The completion of the programme was commemorated by the erection of the Fire Monument. Designed and paid for by John Bastard and located on the eastern side of the market place in 1760, it stands "in grateful Acknowledgement if the Divine Mercy, that has raised this Town, like a phoenix from it's ashes, to its present beautiful and flourishing State."
The commercial prosperity of the town was greatly enhanced by the deliberate destruction of the neighbouring market town of Milton Abbas between 1771 and 1790 by the Earl of Dorchester, who replaced it with a more modest model village. Blandford Forum grew steadily in the nineteenth century with the development of housing along Dorset and Orchard Streets, and later after the arrival of the railway, in streets running off from Salisbury Road.