Hi Aswini,
Not sure about the starting version, but according to the documentation it shows as 0.8.6 and prior -
Documentation/ReleaseNotes/ReleaseNotes-Old – SAPUI5 Wiki (TIP CORE User Interface)
You can see a nice blog written by Andreas to know more about UI5 Intro, history etc.
Regards,
Sai Vellanki.