Directions (1-5): Read the following passage carefully and answer the questions given below it in the context of the passage.

Bluetooth is the anglicized form of the Danish word Bletand - Ble meaning blue- the victory title given to the 10th century King Harald Gormsson. Harald was born in circa 935 and ruled as King of Denmark around 958 and as King of Norway around 970. Bluetooth technology was invented in 1994 by Swedish company Ericsson, which found it appropriate to name it after the Scandinavian king who had united several Danish tribes and parts of Norway into a single kingdom. The implication is that a Bluetooth does the work of uniting different communication protocols into one universal standard.

Question: 1 - The term circa used before '935' in the passage means—