US racing welcomed its 13th Triple Crown hero last month when Justify took the Grade 1 Belmont Stakes in style in New York, just three years after American Pharoah swept the classic series. The previous horse to achieve the feat had been Affirmed, back in 1978, one year after Seattle Slew.

The original Triple Crown is the English series of the 2000 Guineas, Derby and St Leger, and no horse has successfully completed it since Nijinsky in 1970. In 1985, Oh So Sharp won the 1000 Guineas, Oaks and St Leger – called the Fillies' Triple Crown – something that had not been done since Meld, in 1955.

There have been horses who have won two legs, and since Nijinsky those have been Nashwan, Reference Point and Sea The Stars.

Nashwan, whom Timeform rated 135, bypassed the St Leger in favour of an Arc attempt that ultimately did not happen, whereas many believed that, like Blue Peter in 1939, it was sheer bad luck that denied the Sir Henry Cecil-trained Reference Point his chance at history in 1987. The Timeform 139-rated champion missed the Guineas due to illness. Sea The Stars, of course, did win the Prix de l'Arc de Triomphe after bypassing Doncaster; Timeform rated him 140.

Camelot, however, ran in all three classics and, in 2012, he came so close to becoming the 13th winner of the Triple Crown (16th if you include the three who won the races when they were all held at Newmarket during World War I). A mile Group 1 winner at two, he won the 2000 Guineas by a neck from French Fifteen, trounced Main Sequence by five lengths at Epsom, and failed by just three-parts of a length to beat the ill-fated Encke at Doncaster. In between those latter two classics he added the Irish Derby at the Curragh, beating Born To Sea by two lengths.

Camelot won the Group 3 Mooresbridge Stakes and chased home Al Kazeem in the Group 1 Tattersalls Gold Cup from four starts at four, and he retired to Coolmore Stud with a top Timeform rating of 128. Now he is a star member of Europe's sophomore stallions, with seven stakes winners in his first crop, one already in his second, and a first Group 1 classic winner to his name.

That rising star is Latrobe, who beat Rostropovich and Saxon Warrior by a half-length and neck in the Group 1 Dubai Duty Free Irish Derby at the Curragh last week. He was ridden by Donnacha O'Brien, the now triple classic-winning teenager whose brother Joseph trained the winner and father Aidan supplied the second, third, fourth and fifth.

Latrobe had been runner-up to James Cook in a mile maiden on soft ground at Leopardstown on his only start at two, was a neck second to Hunting Horn over 10 furlongs on softer ground at Naas in April, then chased home Platinum Warrior in the Group 3 Gallinule Stakes before running away with a 12-furlong Curragh maiden three weeks before his classic success.

Latrobe, who was bred by Sweetmans Bloodstock, was originally bought by Margaret O'Toole for €88,000 in Goffs as a foal and then sold on to Joseph O'Brien for 65,000gns from Book 1 of the Tattersalls October Yearling Sale in Newmarket.

He is the third foal of six-furlong, three-year-old polytrack winner Question Times (by Shamardal), who earned her blacktype when runner-up in a listed contest over six furlongs at Newmarket as a two-year-old, and both of his older siblings are multiple winners.

Entangling (by Fastnet Rock) won over 10 furlongs at Yarmouth and 12 furlongs on the polytrack at Kempton last year, whereas that one's full-sister Diamond Fields won the Group 3 Gladness Stakes at Naas first time out as a four-year-old having been Grade 2-placed in the USA the previous season.

Forever Times (by So Factual), the grandam of Latrobe, won six times from five to seven furlongs, all on turf and mostly on good or fast ground, and that mare's other offspring include Group 3 Sceptre Stakes winner and Group 1 Cheveley Park Stakes runner-up Sunday Times (by Holy Roman Emperor).

Classical Times (by Lawman), a four-year-old daughter of Sunday Times and, like her dam, trained by Peter Chapple-Hyam, won the Listed Cecil Frail Stakes at Haydock in late May and was third in the Group 3 Chipchase Stakes over six furlongs on the tapeta at Newcastle last Saturday.

As you might expect of a daughter of Group 1 Nunthorpe Stakes scorer So Factual (by Known Fact), Forever Times is a half-sister to some speedy horses, and although Majestic Times (by Bluebird) won a listed sprint, Welsh Emperor (by Emperor Jones) is the more notable of her half-brothers.

That 13-time scorer was trained by Tom Tate, he won the Group 2 Hungerford Stakes, the Group 3 Bentinck Stakes, and two listed contests, he chased home Toylsome in the Group 1 Prix de la Foret, failed by just a neck to beat Caradak in another edition of that same contest, and he was short-headed by Group 1 Lockinge Stakes heroine and subsequent Group 1-producer Red Evie when bidding for a repeat success in the Hungerford.

Latrobe holds entries in the Group 1 Juddmonte International Stakes and Group 1 Comer Group International Irish St Leger and connections – he is owned by Lloyd Williams – have spoken of a possible Group 1 Melbourne Cup bid. Will he stay 14 furlongs or two miles?

If only his sire mattered then you would have little doubt that such distances would be within his compass, but the amount of speed on the distaff side of his family casts a shade of doubt.

He clearly stays 12 furlongs, however, and that suggests that it is not the speed element of the female side of his family that he has inherited from his dam but, instead, possibly the middle-distance side of his broodmare sire, Shamardal (by Giant's Causeway). That stallion, the son of a star mile to 10-furlong colt and grandson of an Irish Oaks heroine, gets his best winners over a wide range of trips.

It will be interesting to see how the racing career of Latrobe turns out, and with a Timeform rating of 119p he still has a lot of progress to make if he is going to hit the very top, but he is progressive, looks likely to stay at least 14 furlongs, and he could do well on the international circuit.

Merchant Navy (by Fastnet Rock) was a listed and Group 3 scorer for trainer Ciaron Maher, switched to Aaron Purcell, and then got up on the line to take the six-furlong Group 1 Coolmore Stud Stakes at Flemington in November.

He was only beaten by half a length when Group 2-placed on his next start, then by a neck when third to Redkirk Warrior in the Group 1 Newmarket Handicap in March, over the course and distance of his major win. With a stallion berth at Coolmore Australia already secured, he had one more mission to complete.

For that he travelled to Europe and joined the all-conquering Aidan O'Brien stable. Winning the Group 1 Diamond Jubilee Stakes at Royal Ascot was that target, but first he had a warm-up in the Group 2 Weatherbys Ireland Greenlands Stakes at the Curragh.

There was a possible hitch due to the weight he would have to carry in both races. When racing in the northern hemisphere he is counted as being a four-year-old as he was born before 1st January 2015. His actual date of birth is 14th November 2014, making him a late-season three-year-old in his native land, but not entitled to that weight allowance when running here. So, in effect, he was carrying penalties in both his European starts, which makes his performances more meritorious.

Calculating that based on what a three-year-old receives from an older horse at this time of the year is perhaps not the accurate way to do it as, again, he did it as a late-season three-year-old, just shy of being classed as a four-year-old in his home territory.

It was close, very close, and also quite fortunate given how the race went for the runner-up, but Merchant Navy held on by a short-head to take the Ascot feature from the French colt City Light, with American challenger Bound For Nowhere third and English runner The Tin Man fourth. Mission accomplished.

There was some brief speculation about whether or not he would remain a bit longer, to take up his entry in the Group 1 Darley July Cup at Newmarket, but that soon ended. Merchant Navy is in quarantine for a return trip to Australia.

His performance at the Curragh was an outstanding one. The race is for older horses and, rather than receive a weight allowance for being three, he not only met his rivals on their terms but had to give them 3lbs on top because of his Group 1 success in Australia.

Despite all of this, he beat Spirit Of Valor by a length, with Tasleet another length and a quarter back in third and an additional neck back to Brando in fourth.

So, Merchant Navy returns home with two notable European wins to his name, plus a Timeform rating of 126 and a profile that will make him an attractive prospect for breeders should he return in the spring as a reverse-shuttle stallion.

He was bred by Chris Barnham, and although there as aspects of the distaff side of his family that won't be familiar to many here, his sire needs no introduction.

Fastnet Rock (by Danehill) is one of the most successful of all the reverse-shuttle stallions and his global tally of 137 stakes winners includes 35 who have won at the highest level, including the European-trained Group 1 stars Diamondsandrubies, Fascinating Rock, Intricately, Laganore, Qualify, Rivet, and Zhukova.

All but two of that list are fillies, Fascinating Rock is a member of the stallion team at Ballylinch Stud, and this male line got another advertisement at the Curragh this afternoon when Urban Fox, a daughter of Australian Group 1 scorer Foxwedge (by Fastnet Rock) – who reverse-shuttled to Whitsbury Manor Stud for four seasons – sprang a surprise in the Group 1 Juddmonte Pretty Polly Stakes.

Merchant Navy is out of the Group 1-placed, Group 3-winning sprinter Legally Bay (by Snippets) and that makes him a full-brother to Jolie Bay. Also bred by Barnham, she was a short-head winner of the Group 2 Roman Consul Stakes over six furlongs at Randwick a month before chasing home Nechita in the Group 1 Coolmore Stud Stakes over the same trip at Flemington.

Their dam is among a string of winners produced from the seven-furlong and mile scorer Decidity (by Last Tycoon) and those siblings include three of note. The prolific Bonaria (by Redoute's Choice) won the Group 1 VRC Myer Classic over a mile, Time Out (by Rory's Jester) was a six-furlong Group 3 scorer as a juvenile, and four-time sprint winner Chatoyant (by Flying Spur) made her name at stud.

​That mare's best are by stallions who are very familiar to those in this part of the world. Smart two-year-old Montsegur (by New Approach) won a five-and-a-half-furlong Group 3 at Caulfield and one over six furlongs at Flemington, whereas Tessera (by Medaglia d'Oro), who was stakes-placed at seven, got his best win in a five-and-a-half-furlong juvenile Group 3 contest at Rosehill.

Decidity was out of Class (by Twig Moss), which made her a half-sister to nine-furlong Group 2 scorer Classy Fella (by Kenmare) and what could be described as being a three-parts sister to 12-furlong Group 3 winner Vestey (by Last Tycoon).

It is not impossible that some of the talented future offspring of Merchant Navy will also stay that distance, although it seems likely – given his racing profile and the achievements of those most closely related to him – that he will mostly get sprinters and milers, along with some who will be effective at 10 furlongs.