Historically, mourning period was considered an integral part of human's life.

Even though its lenght, depending on the type of personal loss, was regulated by social rules, dictating

the behaviour and dress of the mourner, it also provided a certain amount of freedom, otherwise unobtainable. Mourning was not an act, it was a state to enter - almost a place to be.

A mourner was disconnected from the outside world, and, especially in the Victorian Era, was believed to live in the death's shadow or even being accompanied by the loved one's ghost.

Taking a step back from the society and abstaining from certain activities was considered a natural part of the healing process, necessary to cope with the experience of loss.

Even though the lenght of the mourning period was socially regulated (it could last from few

months to two years), it was acceptable to prolong it even until the end of one's life. In the high society, mourners were the only people allowed to express any strong emotions in public without being considered vulgar or ridiculous.

 The tradition of wearing black colour as a sign of mourning dates back to Ancient Rome.

Since the 14th century this colour, often associated with death, darkness and grief,  was also considered as a sign power and wealth. As the black dye was difficult to obtain and therefore expensive, black clothes were considered very elegant and became popular amongst royals and nobility.
Black could also be worn as a sign of religious or political beliefs. It became more common after the French Revolution and was treated a symbol of national grief in 1860s Poland. 

Mourning was considered not only an inevitable part of human life, but also a socially

acceptable choice. Regardless of the era and geographic location, it seems to have always been one of the most respected of human rights.

Even though the conclusion of this state was usually not abrupt, but rather followed

by a transitional period of half-mourning, the only real occurrence that could end mourning

was an individual decision.