Last updated on .From the section European Football

When Julian Nagelsmann was born in 1987, Bayern Munich boss Carlo Ancelotti had already won four Italian cups and one championship as a player

When Hoffenheim unveiled Julian Nagelsmann as the Bundesliga's youngest full-time boss in February, it was dismissed by local media as a "public relations stunt" and "a crackpot idea".

Harsh, perhaps, but understandable given the circumstances.

Nagelsmann was just 28 and had never coached at senior level, while Hoffenheim, a village with a population of just 3,300 in southern Germany, were deep in relegation trouble, seven points from safety and running out of games.

What has followed in the past nine months is impressive.

Not only did Nagelsmann secure the club's Bundesliga place, but he has also seen his side move up to third in the table this season and become one of only five teams in Europe's five major leagues to remain unbeaten.

So, how has a managerial novice born in 1987 managed to transform Hoffenheim from relegation strugglers to a top-three side?

BBC Sport looks at the 29-year-old who has taken the German top flight by storm.

'Baby Mourinho'

Long before he landed the head coach role at the club, Nagelsmann had already earned the nickname 'Baby Mourinho'.

It was given to him by former Hoffenheim and Germany goalkeeper Tim Wiese as Nagelsmann was making a name for himself after the defender's career was cut short by persistent knee problems.

Like Manchester United manager Jose Mourinho, Naglesmann did not make it as a top player. Aged 20, he was forced to end a promising career while in Augsburg's second team, coached by Thomas Tuchel, who is now manager at Borussia Dortmund.

Nagelsmann then worked under Tuchel before moving to Hoffenheim via coaching 1860 Munich's Under-17s.

He then appeared on Bayern Munich's radar after masterminding Hoffenheim's German Under-19 Championship triumph in 2014, but he opted to stay at the Rhein-Neckar-Arena. And his appointment as head coach came six years after arriving at the Sinsheim-based club.

Hoffenheim's head coach Julian Nagelsmann, 29, and director of football Alexander Rosen (right), 37, have a combined age younger than 67-year-old Arsenal boss Arsene Wenger

"I assumed a big deal would made about my age when I was appointed," Nagelsmann told BBC Sport.

"If you are appointed a boss of an established economic enterprise at the age of 28, this also would be a big story."

From relegation strugglers to top three

Hoffenheim had two wins from 20 games when Nagelsmann took charge nine months ago. They were next to bottom in the table and seven points from guaranteed safety.

Local newspaper Rhein-Neckar-Zeitung labelled his appointment a public relations stunt. external-link

"I don't blame them," Hoffenheim's director of football Alexander Rosen said. "You look at Julian's age. He had already been here six years so we knew what he was able to do.

"He has a natural feeling for the group, he brings energy, passion and is blessed with talent."

Hoffenheim won seven of the remaining 14 games to finish one point above the relegation play-off spot.

Hoffenheim are in their ninth successive season in the Bundesliga

"Straight away the team bought into my ideas and the way I would like to play football," added Nagelsmann, who lists Johan Cruyff and Pep Guardiola as his footballing heroes.

Hoffenheim had announced in October 2015 that the youth coach would take over as manager in the summer of 2016, provided they stayed up.

However, Nagelsmann was fast-tracked into the job with three months of the season remaining when experienced boss Hubb Stevens resigned because of a heart complaint.

And Nagelsmann's sense of technical know-how and ability to man-manage has converted critics into admirers.

"He had some experience in coaching but not as a head coach," said Joachim Klaehn, who covers Hoffenheim for the Rhein-Neckar-Zeitung newspaper.

"Before Julian was appointed, they were in big trouble. They were bottom of the table during the winter break and everybody thought they would go down as they had no match plan.

"But it has been a sensation under Julian. He is a local hero."

With Hoffenheim's place in the Bundesliga secured, Nagelsmann got to work on rebuilding the squad in the summer.

Incomings included Croatia forward Andrej Kramaric, 25, who turned a loan from Leicester City into a permanent move, midfielders Lukas Rupp, 25, from Stuttgart and Kevin Vogt, 25, from Cologne, plus former Bayern Munich forward Sandro Wagner, 28, from Darmstadt.

Hoffenheim are two places above Borussia Dortmund, who finished second last season

Hoffenheim have scored in all but two of their 24 league games under Nagelsmann and even took the lead at champions Bayern Munich, managed by three-time Champions League winner Carlo Ancelotti.

"I have great respect for a coach like Ancelotti. Every coach dreams of being able to celebrate only a fraction of his achievements," added Nagelsmann, who was raised in the Bavarian village of Issing.

Since their young coach took charge, Hoffenheim have taken 43 points in 24 matches. But Rosen warned there will be times in the future when it may not be so rosy.

"He is an extraordinary talent," he said.

"However, we have to keep in mind the possibility that we will lose two or three games in a row. We have to be careful we give Julian the air to breathe when things are not going well.

"Let's not forget he has had 26 league and cup games as head coach, he is still learning."

Age concern?

How has Nagelsmann's appointment gone down with the senior players in the dressing room?

For starters, Hoffenheim have no major stars in their team after Roberto Firmino left for Liverpool in June 2015.

Instead they have assembled a squad of hard-working individuals, with the club operating a policy of signing young talent.

That means only three players are older than the head coach - second-choice goalkeeper Alexander Stolz, 33, Poland midfielder Eugen Polanski, 30, while Switzerland midfielder Pirmin Schwegler is 136 days older than his boss.

"We have eight players from our own academy in the first team squad," added Rosen. "For the past three years we have had the youngest squad in the Bundesliga."

Relaxed off the training pitch, Nagelsmann has been accused of being the opposite in his technical area.

Bayer Leverkusen head coach Roger Schmidt was banned and fined after calling his opposite number a "nutcase" during a game in October.

"I act out my emotions on the sidelines. I am also a very impulsive person and very involved in the speech to my players, but only as far as motivation is concerned," he added.

"I do not yell at my players because they made a mistake or rage in the dressing room," Nagelsmann said. "Of course, sometimes you get angry or your voice gets louder when you analyse a match but everything stays within the limits."

Village team to Bundesliga

Hoffenheim, a former village team, were playing in the eighth tier of German football when former player Dietmar Hopp returned to buy the club in the early 1990s.

Hopp brought with him his personal fortune, made from a software company, and a dream to take his former club to the top level of German football.

Initial investment came in the form of modern training facilities and the large-scale development of youth academies.

This provided the foundations that saw a fairytale rise through the divisions with a team made up entirely of products of the youth set-up.

Hoffenheim were an amateur village team when Julian Nagelsmann was born in 1987. This season their average crowd is 26,665

After rising to the second tier of German football, Hopp saw the opportunity and for the first time invested heavily in the squad and management.

Former Schalke boss Ralf Rangnick was appointed boss in 2006, and subsequently helped the club to back-to-back promotions, realising Hopps' long-term vision of making Hoffenheim a Bundesliga club.

This is their ninth season in Germany's top tier.

The Rhein-Neckar Arena, which holds 30,000 fans, has been their home since January 2009 and is situated in the southern town of Sinsheim, which is a short car ride from Hoffenheim.

What they say

Bayern Munich boss Carlo Ancelotti: "It is rare to observe such a young coach in the job. I hope that one day he will train the best team in the world."

Borussia Dortmund boss Thomas Tuchel: "He's a very inquisitive and very hardworking young coach. He has enjoyed exceptional successes in youth football. I'm very happy for him and I believe in him."

Hoffenheim director of football Alexander Rosen: "Julian is 29 and I am 37. We have a combined age younger than [Arsene] Wenger!

Hoffenheim's 76-year-old owner Dietmar Hopp: "He's so good that I wonder if we can keep him. It would be best if we could keep him for a long time, at least as long as I live, and I hope that's quite a long time."

Young at heart

Although Nagelsmann is the youngest permanent head coach in Bundesliga history, he is not the youngest to oversee a Bundesliga match.

That honour belongs to Bernd Stober who was just 24 when he took charge of Saarbrucken in an interim capacity for their trip to Cologne on 23 October 1976. His side lost 5-1.

In Europe's other major leagues, Crystal Palace put Attilio Lombardo in charge at the age of 32 years and 67 days in 1998, while Lippo Hertzka had just turned 26 when he was appointed Real Madrid boss in 1930.

In France, Henri Cammarata was 29 years and 11 days old when he took charge of his first Toulouse match in 1945.

Former England striker David Platt was 32 years and 187 days old when he was appointed by Sampdoria in December 1998.

David Platt (left) played for Sampdoria alongside Ruud Gullit in 1993-94 before the former England striker returned to take charge of the Italian club in 1998

That was the year

Nagelsmann was born on 23 July 1987. By then...