Zisa or Cisa is a potential goddess in Germanic paganism associated with the Suevi in the area of Augsburg, Germany. Zisa is mentioned in manuscripts from the 12th to 14th centuries which reference a victory against the Roman Empire attributed to the goddess. The anniversary of this victory was celebrated on the festival day of September 28 and involved games and merrymaking.
19th century scholar Jacob Grimm proposes a connection between Cisa and to the "Isis" of the Suebi attested by Tacitus in his 1st century CE work Germania based on the similarity of their names, if not their functions. Zisa is as an etymological double of Tyr or Ziu and Grimm suggests that Zisa may be the same figure as Tyr's unnamed wife, mentioned by Loki in the 13th century Poetic Edda poem Lokasenna. Grimm also references a record of a pagan Duke of Swabia named Esenerius who established a chapel in his castle in Kempten (then known as Hillomondt) with a venerated image of Zisa.
Scholar Rudolf Simek dismisses Zisa, explaining that "today the supposition of the goddess Cisa is rejected because the source text does not stand up to critical examination" and cites a work from 1936. On the other hand, scholar Stephan Grundy, and authors Nigel Pennick and Prudence Jones, present the source as potentially valid.
Pennick references two Medieval manuscripts which mention Zisa, Codex Monac circa 1135 and Codex Emmeran circa 1135, along with a corroborating third source, Melchior Goldast's Suevicarum rerum scriptores. These three are based on a first century BCE record of a Swabian military victory over Roman forces. The record mentions a city where the inhabitants worshipped Zisa "with extreme reverence". Pennick identifies this city as ancient Augsburg, and further identifies the depiction of the red-dressed woman in the Golden Hall of the Augsburg Town Hall as one of Zisa.