By the late 1950s, the British had provided Oman with considerable diplomatic and military support that allowed the Sultan to extend his influence inland and defeat an insurgency. One of the most significant turning points in the history of Anglo-Omani relations occurred in 1958 when the so-called ‘agreed minute’ was signed committing the British government to extensive defence cooperation and development. The Sultan extracted considerable economic and military support from the British without making any significant concessions. Military support for the Sultanate reached its apotheosis in early 1959 when the Special Air Service Regiment (SAS) assaulted the impregnable Jebel Akhdar effectively ending the insurgency in northern Oman.