The Sabaeans were an ancient people who lived in what is today Yemen in the 1st millennium BC and spoke an earlier version of a South Semitic language. They may be the same nation as the biblical kingdom of Sheba. They made substantial profits off the Spice trade, especially Frankincense, and left behind many inscriptions in the musnad (Old South Arabian) alphabet.
They were polytheistic, and should not be confused with the Sabians mentioned in the Qur'an, whose name is written with the Arabic letter sad rather than sin, and is widely believed to refer to the Mandaeans.