Why is amar singh thapa called 'the living lion of nepal'?

Amar Singh Thapa was the General of the Nepalese forces of western front in the Anglo-Nepalese War. He is regarded as one of the National heroes of Nepal ... Amar Singh Thapa also Built a temple of the goddess Ganga in the early 18th century. The town of Gangotri in Uttarakhand, India is centred around this temple.