Most major sports acquired written rules within a few decades of each other, and the reasons had more to do with organisation than with the games themselves.
Before codification
Games existed in local variants with rules agreed before play or determined by custom.
Which worked while play was local, since everyone knew the local version.
It failed as soon as teams from different places wanted to play each other.
The schools
Educational institutions played versions that differed between them.
Which meant former pupils from different schools could not play together after leaving.
Meetings to agree common rules followed, and the disagreements at those meetings produced the splits that created separate sports.
The division between codes that permit handling and those that do not originates in exactly such disagreements.
Why the period
Railways made travel between towns practical, which created demand for inter-town competition.
Urbanisation concentrated populations, providing both players and spectators.
Reduced working hours created leisure time.
And organisational forms — clubs, associations, leagues — spread as models.
Which together produced the conditions for organised competition, and codification followed necessity.
Governing bodies
Associations established to administer rules, organise competition and resolve disputes.
Which acquired authority over the sport internationally as the model spread.
Their structures, established in that period, largely persist and have been criticised as unaccountable given what they now control.
Amateurism
Rules prohibiting payment to players were introduced in several sports.
Which functioned partly as class exclusion, since only those with independent means could afford to play without payment.
Disputes over this produced permanent splits in several sports, with professional and amateur codes developing separately.
Most have since abandoned the distinction, in some cases very recently.
The standardisation of equipment
Pitch dimensions, ball specifications and equipment standards followed rule codification.
Which was necessary for meaningful competition and for record comparison.
Governing bodies maintain these specifications, and changes to them are consequential and contested.
Records
Comparable records require standardised conditions, which is why athletics specifies track surfaces, wind conditions and measurement methods.
Which means a performance under non-conforming conditions is not recognised regardless of what was achieved.
What continues to change
Rules change continuously in most sports, driven by safety evidence, by broadcast considerations and by tactical developments that exploit existing rules.
Which means the codes established in that period were a starting point rather than a settlement, and the process that created them continues.
Doping
Performance enhancement has existed throughout organised sport, and systematic anti-doping is recent.
Which produced international agencies, testing programmes and prohibited lists updated annually.
Detection and evasion have developed together, and retrospective testing of stored samples has produced sanctions years after competition.
Broadcasting
Television revenue transformed the economics of sport within decades.
Which changed scheduling, rules and presentation to suit broadcast, and it concentrated money in the sports and competitions that attracted audiences.
Sports without broadcast appeal have struggled correspondingly, which affects participation and funding.
Women's competition
Excluded formally from many sports for much of their organised history.
Which was justified variously on medical grounds that were not supported and on social grounds that were explicit.
Formal exclusion was removed progressively over the twentieth century, and participation and funding disparities persist and have been narrowing.
Technology in officiating
Video review, goal-line technology and tracking systems have been introduced across many sports.
Which improves accuracy on specific decisions and introduces delay and new categories of dispute.
The threshold for intervention — whether review corrects clear errors or re-examines every decision — is where most controversy concentrates.
Governance reform
International federations have faced sustained criticism regarding transparency, accountability and corruption.
Which produced investigations, prosecutions and governance reforms in several bodies.
Structures established a century ago, with limited external accountability, now administer enormous sums.
Athlete welfare
Safeguarding failures across multiple sports have been documented through inquiries.
Which produced independent reporting mechanisms, mandatory training and, in several countries, dedicated safeguarding bodies.
The pattern of institutions prioritising reputation over athlete protection recurs across the inquiries.
Classification and eligibility
Rules determining who may compete in which category.
Which are contested in several sports and involve genuine tensions between inclusion, fairness and safety.
Scientific evidence in this area is limited and is being generated, and policies differ substantially between governing bodies.
Participation and elite sport
Investment in elite performance and in mass participation are frequently assumed to be connected.
Evidence for elite success driving participation is weaker than commonly claimed, with effects that are short-lived where they appear.
Which matters for how public funding is allocated between the two.
Grassroots infrastructure
Facilities, coaching and volunteer administration underpin participation and receive far less attention than elite competition.
Which depends substantially on local authority provision and on volunteers, both of which have been under pressure.
Facility closures have measurable effects on participation in the affected areas.
Which is where most people actually encounter organised sport.