The first to decide to dig the Corinth Canal was Periander, the tyrant of Corinth in 602 BC. Such a giant project was above the technical capabilities of ancient times so Periander carried out another great project, the diolkos, a stone road, on which the ships were transferred on wheeled platforms from one sea to the other
The most serious try was that of Emperor Nero (67 AD). He had 6,000 slaves for the job. However, he was killed before the work could be completed. In the modern era, the first who thought seriously to carry out the project was Capodistrias (c.1830), the first governor of Greece, after the liberation from the Ottoman Turks, although due to lack of funds they had to stop.
The work was restarted in 1890, by a new Greek company and the job was finally completed and regular use of the Canal started on Oct 28, 1893.