AIDAN O'BRIEN'S Frozen Fire looks like being the latest Irish Classic prospect to try and book a Derby ticket when he tackles the Epsom favourite Twice Over in Thursday's Dante Stakes at York.

The Dante is the last, and often the most informative, Derby trial and this week's renewal may be vital in clearing up what has been a rather muddy blue riband picture up to now.

Last weekend was a mixed one for O'Brien as the champion trainer attempts to formulate his team for Epsom, with Alessandro Volta winning at Lingfield but Washington Irving well beaten by Casual Conquest at Leopardstown.

Kingdom Of Naples had been touted as a possible Dante contender but yesterday O'Brien reported: "Frozen Fire is a more likely runner now. Plan is a possible runner in the race as well. He seems fine since running in the Guineas."

Both colts are currently 40 to 1 shots for Epsom in ante-post betting but a good display by either could see them shorten dramatically in the market. Frozen Fire won his maiden at Gowran last August and finished eighth in the Racing Post Trophy at Doncaster on his only subsequent start.

The Guineas hero Henrythenavigator is currently the shortest-priced O'Brien entry in the Derby but definite plans for Epsom are still a long way from being drawn up at Ballydoyle.

"We are happy the horses are running well in their trials. None of them have run bad," O'Brien said. "The situation with Henry is still the same. He is still a possible for Epsom."

The Classics focus at York tomorrow will centre on the Musidora Stakes where O'Brien's once-race maiden Moonstone will tackle the current Oaks favourite, Dar Re Mi, as well as Jim Bolger's Lush Lashes.

Both Irish fillies are among a final field of eight, while there will also be significant interest in the Duke Of York Stakes, with Kevin Prendergast's Haatef joined by the Ballydoyle pair, US Ranger and Honoured Guest. Johnny Murtagh is likely to be on board US Ranger.

The Group One international focus this weekend will be on the older horses and although O'Brien said yesterday he is unlikely to run any of his five entries in Sunday's Prix d'Ispahan at Longchamp, he could run two horses in Newbury's Lockinge on Saturday.

The Ballydoyle trainer left in four at yesterday's forfeit stage but Duke Of Marmalade is still likely to wait for the following weekend's Tattersalls Gold Cup, leaving Haradasun and Astronomer Royal as possible runners at Newbury.

The Epsom Oaks is the likely target for John Oxx's smart filly Katiyra, who finished runner-up to Carribean Sunset on her first start of the season at Leopardstown on Sunday. Katiyra got a clean bill of health yesterday and Oxx said: "We were slightly disappointed she didn't win but she didn't get a straightforward run and the winner is a very good filly. Our horse ran an excellent race. She just looks like she needs further. No final decision has been taken but it looks like she will go for the Epsom Oaks and miss the Irish Guineas."

Killarney's May festival winds up this afternoon and the finale sees an interesting runner in Solwhit who runs on the flat in the mile and three quarter conditions race. Séamus Heffernan takes the ride on the ex-French runner who won at Enghein last November before an encouraging first run for Charles Byrnes in April.

Legendary Sadler's Wells retires

A remarkable era in bloodstock history came to an end yesterday when it was confirmed that Coolmore Stud's legendary stallion Sadler's Wells has been retired due to declining fertility, writes Brian O'Connor.

The 27-year-old horse, generally regarded as the most significant European-based sire of the last 50 years, will see out his remaining days at the Co Tipperary farm.

"Despite his advancing years he is still in remarkably good shape and we hope he enjoys a long and happy retirement," said the Coolmore spokesman, Christy Grassick.

Sadler's Wells was champion sire in Britain and Ireland on 14 occasions, including 13 years in a row, and produced Derby winning champions like Galileo, Montjeu and High Chaparral, all of whom are now stallions at Coolmore themselves.

Sadler's Wells' fee was private but at his peak it's believed a nomination to him cost in the region of £150,000.