The Sun Monument obelisk in the grounds of Wentworth Castle erected in 1747 by William Wentworth, the Second Earl of Strafford (of the second creation), to celebrate the “intellectual achievements” of Lady Mary Montagu. She introduced the technique of inoculation against smallpox to Britain and through her persistence and power of persuasion, it was taken up by Queen Caroline who decreed that the royal children and future heirs to the throne should be inoculated against the disease. The Sun Monument is the only Georgian monument to a woman erected in her lifetime. Originally the gilded sheet copper orb at the top of the obelisk was intended represent her intellect and, possibly more importantly, to be an eye-catcher from the surrounding landscape beyond the park. The orb was missing so needed to be replaced in order to complete the iconography.
A new threaded finial and base were fabricated from bronze and the copper orb was fabricated in two halves welded together. All of the assembled components were painted with a red oxide primer, followed by two coats of a yellow bole and finished with two coats of gold leaf prior to installation on the top of Sun Monument from an hydraulic access platform.