Ambo. From Enc. Britt.: in the Christian liturgy, a raised stand formerly used for reading the Gospel or the Epistle, first used in early basilicas. Originally, the ambo took the form of a portable lectern. By the 6th century it had evolved into a stationary church furnishing, which reflected the development and codification of the Christian liturgy. By the Byzantine and early Romanesque periods, it had become an essentialpart of the church plan. In the 12th century, the ambo was gradually superseded by the pulpit, and it passed out of liturgical use.

I was informed by a viewer: this destroyed ambo originates from Thessaloniki, from Rotonda. It represents the adoration of the 3 kings.