It is narrated from Sayyiduna Ghaylan bin Salamah al-Thaqafi (may Allah be pleased with him) that Nafi' was the slave of Ghaylan bin Salamah. He fled (while Ghaylan was a polytheist) to the Messenger of Allah (peace and blessings be upon him) and accepted Islam, while Ghaylan was at that time a polytheist. Then Ghaylan also accepted Islam, and the Messenger of Allah (peace and blessings be upon him) returned his wala' (the right of patronage over the slave) to him.
Hadith Referenceالمعجم الكبير للطبراني / باب الغين / 15750