The Hydra Bronze Cloth is the cloth of the Saint Ichi in Saint Seiya and Saint Seiya: Omega, and Curtis in Saint Seiya: The Lost Canvas. It is of the lowest class of the cloths that Athena’s Saints wield, the Bronze Cloth.
The constellation of Hydra was based on, in one view, by the Lernaean Hydra who regrew his mortal heads as they died, and had an immortal head, which made him all but unstoppable until Heracles beheaded the heads, had their necks burned, and buried the immortal head under a large rock, ending its threat.
Ichi trained to be a Saint in Lake Holtz, Finland during the period the other orphans were. The cloth was likely kept in this area by his master to be given to one who was proved to be a Saint. During The Lost Canvas, Curtis is the Saint who receives the Hydra Bronze Cloth. It is not revealed where he got his cloth, having had it since the beginning of the series.