play within 12 yards of the goal line. The umpires are replaced by linesmen. Pitch markings are introduced for the goal area, penalty area, centre spot and centre circle. 1897 – The laws specify, for the first time, the number of players on each team (11) and the duration of each match (90 minutes, unless agreed otherwise). The half-way line is introduced. The maximum length of the ground is reduced from 200 yards to 130 yards. 1901 – Goalkeepers may handle the ball for any purpose (previously the goalkeeper was permitted to handle the ball only "in defence of his goal"). 1902 – The goal area and penalty area assume their modern dimensions, extending six yards and eighteen yards respectively from the goal posts. The penalty spot is introduced. 1903 – A goal may be scored directly from a free kick awarded for handball or foul play (previously all free-kicks awarded for infringements of the laws, other than penalty kicks, had been indirect). A referee may refrain from awarding a free kick or penalty in order to give advantage to the attacking team. A player may be sent off for "bad or violent language to a Referee". 1907 – Players cannot be offside when in their own half. 1912 – The goalkeeper may handle the ball only in the penalty area. 1920 – A player cannot be offside from a throw-in. 1924 – A goal may be scored directly from a corner kick. 1925 – The offside rule is relaxed further: a player is onside as long as there are two opponents between the player and the opponents' goal-line (previously, three opponents had been required). 1931 – The goalkeeper may take four steps (rather than two) while carrying the ball. 1937 – The "D" is added to the pitch markings, to ensure that players do not encroach within 10 yards of the player taking a penalty kick. 1938 – The laws are completely rewritten and reorganised by a committee under the leadership of Stanley Rous. The rewriting introduces the schema of seventeen laws that still exists today. A player may be sent off for "serious foul play". 1958 – Substitutions of injured players is allowed in competitive matches for the first time, subject to national association approval. 1970 – Introduction of red and yellow cards. 1990 – A further relaxation of the offside law: a player level with the second-last