Greek proverb: Ἀρχὴ ἥμισυ παντός

Here's a saying from Apostolius, C3.97, with a Latin version from Clavis Homerica. The image is from Duncan Rawlinson at Flickr. Here are some more Apostolius proverbs.

Ἀρχὴ ἥμισυ παντός.
Principium dimidium totius.
To start is half of the whole.