There is no generally accepted and generally applicable definition of social security. What is most frequently referred to is the whole set of compulsory measures adopted by society to protect the individual and their family against the consequences of an unavoidable interruption or serious diminution of the earned income needed for maintaining a reasonable standard of living. This has the advantage of reducing the field of investigation to more concrete institutional or institutionalised measures, developed over a period of time with a relatively well-defined purpose.

The cause of the insecurity of income is the materialisation of a risk that may be physiological (e.g.accident, illness, old age) or social (e.g. family care, of unemployment). Human society has always looked for ways through which to secure the means of existence of its individual members. As a result of a long historical evolution, social insurance has become the main form of provision against different risks, based on the idea of mandatory pooling of resources of individual citizens to provide benefits in case of need.

Institutional predecessors of social insurance

A historical search for predecessors of social insurance leads us back to at least five different sources representing institutionalised actions aimed at guaranteeing some material security to specific groups of people.

Rewards for services

The first and probably the most ancient form of such an action is reward for services that are rendered to holders of political power in society. This would include the distribution of booty to soldiers and the grants of land and pensions to veterans, or to widows and orphans of soldiers killed in wars, as practised in ancient Rome.

In the same category would be the provisions made by different rulers to those who served their interests and helped them in expanding their territories. Such an example would be found in the first social provisions known in post-Columbian Latin America under the designation of ‘instituciones graciables’, introduced by the Spanish kings for the benefit of the invading armies and later on for all the king's administrators and members of their families (Moles, 1962, pp 33-55).

In more recent times we can find a similar motivation behind social measures taken for the benefit of civil servants.