313. Banished from Venice....

In 1291, practitioners of this art-form were forced to move from Venice to a neighboring island (name blacked out in the figure) as most of Venice was made up of wooden buildings.

Which art-form? Which neighboring island?

312. In the court of King Neptune?

Those who accomplish the feat are nicknamed Shellbacks and those who have not are nicknamed Pollywogs.

After accomplishing the feat, Pollywogs receive subpoenas to appear before King Neptune and his court (usually including his first assistant Davy Jones and her Highness Amphitrite and other assorted dignitaries), who officiate at the ceremony marking their transition to a Shellback.

What feat are we referring to?

311. The new Pheidippides?

The Athens Classic Marathon, an annual event was established in 1983 and has been run annually since, normally in November.

The marathon is dedicated to the memory of someone (pic above), who amongst other things, held the national Greek record for Long Jump for 23 years and whose death caused a symbolic piece of graffiti to come up all over Athens.

Identify this person.