SAID BEG (d. 1703), a Mughal general, in company with another general, Alif Khan, was marching at the head of an army on his way from Lahore to Delhi when the Rajput hill rulers led by Raja Ajmer Chand of Bilaspur persuaded him to join them in an attack on Guru Gobind Singh, who, according to Bhai Santokh Singh, Sri Gur Pratap Suraj Granth, was then camping at Chamkaur on his way back from Kurukshetra. As Said Beg saw Guru Gobind Singh majestically ride his steelblue steed, he felt deeply moved. He left his army and crossed over to the Guru`s side. Alif Khan. Surprised and dispirited by Said Beg`s action also withdrew from the contest. 

Said Beg remained with Guru Gobind Singh and fell fighting for him when another imperial force under General Said Khan attacked Anandpur jointly with the hill rajas in February 1703.

References :

1. Santokh Singh, Bhai, Sri Gur Pratap Suraj Granth. Amritsar, 1927-35
2. Harbans Singh, Guru Gobind Singh. Chandigarh, 1966
3. Macauliffe, Max Arthur, The Sikh Religion. Oxford, 1909