diplomatic corps 
noun
The body of diplomats representing other countries in a particular state.On 19 October, the city went under martial law and the government offices and diplomatic corps began evacuating to Kuibyshev....
- World War I, however, brought revolutions, national democratic movements, and the first wave of anti-imperialism: the aristocratic veneer of the diplomatic corps began to wear thin.
- The Renaissance papacy, infamous for nepotism and corruption, nevertheless went on to contribute innovations in diplomacy, such as resident ambassadors and rules for the diplomatic corps at Rome.