(CNN) -- Football's world governing body, FIFA, has officially sanctioned the wearing of religious headscarves.
The announcement made at the Annual General Meeting of the International Football Association Board (IFAB) in Zurich, Switzerland follows a successful trial period which began in July 2012.
"The IFAB approved the modification to the interpretation of 'Law 4 -- The Players' Equipment' specifying the provisions by which male and female players can now wear head covers," read a statement on FIFA's website on Saturday.
"After a two-year pilot, The IFAB agreed that there was no indication as to why the wearing of head covers should be prohibited..."
FIFA banned the wearing of headscarves in 2007 on the grounds of safety, but the ruling caused controversy.
In 2011, Iran's women's team forfeited a Olympic qualifying match against Jordan because members of their team were prohibited from wearing headscarves.
However, following a request by Zhang Jilong from the Asian Football Federation in January 2012, FIFA unanimously approved headscarves for a trial period six months later.
A further relaxation of FIFA rules came in July 2013 after the Canadian Soccer Federation lobbied FIFA to change rules to allow turbans to be worn on the football pitch.
No more slogans on undershirts
On the same day it was relaxing its position on headscarves, IFAB also announced a tightening up of rules on undergarments bearing slogans.
Until now, some slogans have been allowed but a blanket ban will now be imposed.
"Players must not reveal undergarments showing slogans or advertising. The basic compulsory equipment must not have any political, religious or personal statements. A player removing his jersey or shirt to reveal slogans or advertising will be sanctioned by the competition organiser," FIFA states.
"From now on there can be no slogan or image whatsoever on undergarments even good-natured ones. This will apply from June 1 and will be in force for the World Cup," FIFA secretary general, Jerome Valcke said.
Players frequently lift their shirts after scoring a goal to reveal a range of messages from dedications to new born babies to get well soon messages to players or friends.
But these, along with more colorful statements like Mario Balotelli's "Why always me?" revealed while playing for Manchester City in 2011, will now be banned.
"The idea is to get some consistency. The simplest rule for the image of the game is to start from the basis that slogans will not be allowed," said Alex Horne, general secretary of the English Football Association.