It was improved in the 13th century during the reign of King John and a license to crenellate was granted in the mid 14th century.
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request. ### Instruction: List the MITRE techniques contained in the text. ### Input: It was improved in the 13th century during the reign of King John and a license to crenellate was granted in the mid 14th century. ### Response: .