Given the question: What was restored by Nigel Williams in 1988–1989?  Answer the above question based on the context below:  The highlight of Doubleday's career came after 7 February 1845 when a young man, who later admitted having spent the prior week "indulging in intemperance", smashed the Portland Vase, an example of Roman cameo glass and among the most famous glass items in the world, into hundreds of pieces. After his selection for the restoration, Doubleday commissioned a watercolour painting of the fragments by Thomas H. Shepherd. No account of his restoration survives, but on 1 May he discussed it in front of the Society of Antiquaries of London, and by 10 September he had glued the vase whole again. Only 37 small splinters, most from the interior or thickness of the vase, were left out; the cameo base disc, which was found to be a modern replacement, was set aside for separate display. A new base disc of plain glass, with a polished exterior and matte interior, was diamond-engraved "Broke Feby 7th 1845 Restored Sept 10th 1845 By John Doubleday". The British Museum awarded Doubleday an additional £25 (equivalent to £2,500 in 2016) for his work.At the time the restoration was termed "masterly" and Doubleday was lauded by The Gentleman's Magazine for demonstrating "skilful ingenuity" and "cleverness ... sufficient to establish his immortality as the prince of restorers". In 2006 William Andrew Oddy, a former keeper of conservation at the museum, noted that the achievement "must rank him in the forefront of the craftsmen-restorers of his time." Doubleday's restoration would remain for more than 100 years until the adhesive grew increasingly discoloured. The vase was next restored by J. W. R. Axtell in 1948–1949, and then by Nigel Williams in 1988–1989.
The answer is:
Portland Vase