License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Augostino Aglio, the elder. A Plan of a Triumphal Memorial....at Holyhead in honour of the visit of His Majesty George IV to the Principality of Wales on the 7th of August, 1821 by Thomas Harrison Esq. Architect, ca. 1822. The Metropolitan Museum of Art.