The Marshalsea Prison was erected in 1373, on Borough High Street. Although there are references to it from 1294 on, it appears that there was no dedicated building prior to this date. Around the beginning of the nineteenth century, it moved a short way down the road, to the site previously occupied by the King’s Bench prison.

The Foreigner’s Guide to London, 1730, described the Marshalsea thus:

The Marshalsea; where a Number of miserable Insolvent Debtors are put for small Sums, and are true Objects of Compassion; who there spend a wretched Life, unless some charitable Persons release them, in paying their Debts and Fees; or till the Government discharge them by an Act of Grace, which happens sometimes not once in seven Years.

Bibliography & further reading:

Foreigners Guide, 1730.

Survey of London, vol. 25: Southwark Prisons, 1955.

Wikipedia.