Brief history: Spain are currently defending Champions of the European competition after winning their second title in 2008 adding to their 1964 success.
European appearance: Spain first appeared at the European Championships in 1964 and have only failed to qualify on a couple of occasions.
How they made it: They finished with a maximum 30 points from 10 games with a plus-20 goal difference and 11 points clear of second-place Czech Republic.
Key players: Iker Casillas (Real Madrid), Andre Iniesta (Barcelona), Xavi (Barcelona), Fernando Torres (Chelsea), and Fernando Llorente (Athletic Bilboa).
Coach: Vincente Del Bosque
Strengths: Their midfielders and goalkeepers are among the best in the world. Their midfielders with defence splitting passes should leave the forwards with easy finishing opportunities.
Weakness: Ironically, the strength of their midfield is also their weakness. They are so strong in the centre of the park that their defence is hardly ever tested. With key defender and influential leader Carlos Puyol out through injuries, their defence will be tested.
Expected finish: After brushing away the teams in qualifications, Spain are bound to be favourites to top this group and make it to the final stages.
Brief history: Italy has made it to the Cup finals on two occasions, once in 1968 and the other in 2000. In 1968, they defeated Yugoslavia but in 2000, World Cup champions France claimed the European title.
European appearance: A good tournament team, Italy rarely misses out on the European Championships. After their first appearance in 1968, Italy has been back on six occasions.
How they made it: They qualified atop their group 10 points clear of second-placed Estonia. The Azzuri's (as they are affectionately called), conceded only two goals in 10 games to finish with the best defensive record in Europe.
Key players: Gianluigi Buffon (Juventus), Andreas Pirlo (Juventus), Christian Maggio (Napoli), Antonio Cassano (AC Milan), and Mario Balloteli (Man City).
Coach: Cesare Prandelli
Strengths: With the best defensive record, there will be no prizes for guessing the strength of Italy. A disciplined and robust team, it will take some effort to break down their defence.
Weakness: Paying so much attention to defending, Italy struggled to find goals in the last two major championships and could cause a problem yet again.
Expected finish: Italy is strong enough to make it out of the group stages, but the quarterfinals should be the furthest they go. But then again, if a team does not concede they cannot lose.
Brief history: Once a part of Yugoslavia, Croatia has failed to live up to that legacy, having only qualified to the quarter-finals since the dissolution of the Republic.
European appearance: They have only been to the championships on three occasions: 1996, 2004 and 2008.
How they made it: Having finished second in their group behind Greece, Croatia had to face Turkey in the play-offs. The Croatian ran out 3-0 aggregate winners and booked their fourth appearance at the tournament.
Key players: Niko Kranjcar (Tottenham Hotspurs), Luka Modric (Tottenham Hotspurs), Nikica Jelavic (Everton) and Darijo Srna (Shakhtar Donetsk).
Coach: Slaven Bilic.
Strength: Their midfield and counteracting skills are their strongest assets. Teams that underestimate the skill and vision of Luka Modric or the speed and attacking prowess of winger Darijo Srna will be caught off guard.
Weakness: With an aging back-line, the Croatians defense should be their biggest liability at this years tournament.
Expected finish: The Croatians are not expected to leave this group.
Brief history: In their first and only appearance at the European Championships, Ireland failed to make it out of the group stages, with their only win coming against neighbours England.
European appearance: Ireland has only ever qualified once before in 1988.
How they made it: After finishing second in their group behind Russia, The Irish easily brushed aside Estonia 5-1 in the play-offs.
Key players: Shay Given (Aston Villa), Richard Dunne (Aston Villa) and Robbie Keane (LA Galaxy).
Coach: Giovanni Trappattoni
Strength: Ireland's strength should be their ability to play as a unit and draw on each others strength, as well as the attacking prowess of Robbie Keane, who has an international haul of 53 goals.
Weakness: With Glen Whelan, Damien Duff, and Keith Andrews in the midfield, Ireland's lack of creativity will be a problem as they labour to break down teams such as Italy and Spain.
Expected finish: Ireland should again find the European Championships too much for them and they will be lucky if they get a victory this time around.