During the early period of his reign, Ilyas Shah led the first Muslim army into Nepal. He occupied the Tirhut region and thrust through the Terai plains into the Kathmandu Valley. His army sacked the temple of Svayambhunath, returning to Bengal with plentiful spoils. Ilyas Shah then invaded Orissa, which was ruled by Bhanudeva II of the Eastern Ganga dynasty. He further sacked Jajpur, Cuttack and reached as far as the Chilika Lake. He also led a successful campaign against the Kamarupa kingdom in present-day Assam.