According

According - (Webster's 1828 Dictionary)

ACCORD'ING, ppr.

1. Agreeing; harmonizing.

Th' according music of a well mixt state.

2. Suitable; agreeable; in accordance with.

In these senses, the word agrees with or refers to a sentence.

Our zeal should be according to knowledge.

Noble is the fame that is built on candor and ingenuity, according to those beautiful lines of Sir John Denham.

Here the whole preceding parts of the sentence are to accord, i.e. agree with, correspond with, or be suitable to, what follows. According, here, has its true participial sense, agreeing, and is always followed by to. It is never a preposition.