Page "Three letter rule" Paragraph 3

In Old English, inflections increased the length of most content words in any case.

Through to the seventeenth century, before English spelling was firmly settled, short forms for some content words did occur, such as eg ( egg ), ey ( eye ), lo ( low ), etc.

Conversely, poets such as John Milton alternated between short and long forms for function words, depending on whether they occurred on or off the meter.

For instance: