Is Frankel the real deal? We'll know soon enough.

As he makes his three-year-old debut at Newbury this afternoon, it is worth remembering that this time last year we were hailing a wonder horse in the form of St Nicholas Abbey.

Unbeaten in three starts at two and a runaway winner of the Racing Post Trophy at Doncaster, he was a wellbeaten evens favourite in the 2000 Guineas.

The Aidan O'Brien-trained son of Montjeu has had just one run since, two weeks ago, when well held at the Curragh by Unaccompanied, who was previously second in the Triumph Hurdle!

There are so many things that can go wrong between one season and the next. Horses get injuries, some turn temperamental or simply don't train on. Sometimes they were never as good as we first imagined.

It doesn't always need a winter for a horse to go from Pegasus to pit-pony either. Flat racing is littered with the remnants of over-hyped horses, and while it is a boring platitude, nothing can make a fool of a man like a horse.

A prime example of eyes deceiving us is Leonardo da Vinci. In 1978, he won the Wood Ditton on his debut at three, then gave 7lb to his rivals in the White Rose Stakes in soft ground at Ascot and won by 10 lengths, prompting Pat Eddery to jump off and say the son of Brigadier Gerard was the best he'd ever ridden.

Yet the bubble burst at York. He started odds-on for the Dante, finished fifth behind Shirley Heights, then ran only once more and was beaten again.

The Bruce Hobbs-trained Tromos was the clear winter favourite for the 2000 Guineas having been a brilliant winner of the 1978 Dewhurst stakes and was rated 5lb clear at the top of the European Free Handicap.

He had a Timeform rating of 134. But at three, he was eclipsed by Lyphard's Wish in the Craven Stakes and was sent to America, where he made only a limited impression.

Apalachee was an outstanding juvenile, rated 137 by Timeform in 1973, and was sent off the 4-9 favourite for the Guineas, but was beaten (by 50-1 chance Mon Fils). It was his last race.

The list of brilliant twoyear-olds who failed to maintain their dominance at three is long.

One Cool Cat won four times at two in 2003 - including two Group 1s - but was a well-beaten 15-8 favourite in the Guineas and won just one Group 3 from four other starts. Fulke Johnson-Houghton swore blind that 1968 champion two-yearold Ribofilio "was doped when he ran in the 2,000 Guineas" in 1969.

He did go on to finish second in the Irish Derby and St Leger, however.

The same rumours swirled around Gorytus, who was a top juvenile who promised so much in 1982 until he was mysteriously beaten at 1-2 in the Dewhurst. He never raced again.

Crowned Prince won the Dewhurst and Champagne Stakes and was the 1971 Champion two-year-old in England, but he flopped in the Craven Stakes the following April and was taken out of training (he had developed breathing problems).

At two, Storm Bird won all five starts, was voted Champion in England and Ireland in 1980, but at three he raced only once, finishing unplaced.

Dominant juveniles may simply be more mature than their contemporaries. Six months later, horses with a superior engine may have acquired the adult physique which allows them to exploit it.

Frankel has a good chance of emulating Henry Cecil's Wollow, who landed the Greenham Stakes en route to winning the Guineas in 1976.

But will he go on to become a true champion? Time will tell.