Oxford Concordance Program
The Oxford Concordance Program (OCP) was first released in 1981 and was a result of a project started in 1978 by Oxford University Computing Services (OUCS) to create a machine independent text analysis program for producing word lists, indices and concordances in a variety of languages and alphabets. In the 1980s it was claimed to have been licensed to around 240 institutions in 23 countries.
Source: Wikipedia — Oxford Concordance Program (CC BY-SA 4.0)