In 1252-3, was supposedly granted, by Henry III, (In year 37 of his reign) a Royal licence to crenellate Norwici (Norwich City Wall)

Although this document has been considered by some as a licence to crenellate the current opinion rejects this as a licence to crenellate.

King writes "Dugdale, Mon., iv, 14; habuerunt licenciam communes Norwici includendi eandem villam cum fossis. The Chronicle quoted here dates this to 37 Hen. III (i.e. 1252-3) and also to A.D. 1209, but as we are also told told that this occured 60 years after an event in 1194, it is likely that the regnal year gives the correct reading, more or less." Charles Coulson informs me this was not a licence to crenellate.

Significant later source are;

• King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol2 p313n27
  Dugdale, William [Caley, J., Ellis, H. and Bandinel, B. (eds)], 1817-30, Monasticon Anglicanum (London) Vol4 p14

More details about licences to crenellate can be found here.

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