Trap door for the Portable Altar of Countess Gertrude

Commissioned by Countess Gertrude of Brunswick, this portable altar is one of the Guelph Treasure’s earliest and most sumptuous objects. The choice of white-speckled porphyry as the altar stone signals Gertrude’s worldly aspirations; an imperial color since classical antiquity, porphyry was only used by the imperial family. Historical figures of royal and imperial rank are depicted with Christ, the Virgin, apostles, and archangels along the altar’s sides, stressing the countess’s political ambitions and claim of imperial lineage for her own dynasty. The Latin inscription surrounding the altar stone reads, "Gertrude offers to Christ, to live joyfully in him, this stone that glistens with gems and gold."