Classify the following document as either fiction or non-fiction:

The history of the Vikings is a fascinating and complex story.
The history of the Vikings is a fascinating and complex story.
Non-fiction.
Complete the following task based on the instruction and optional input provided.### Instruction:
Classify the following document as either fiction or non-fiction:

The history of the Vikings is a fascinating and complex story.

### Input:
The history of the Vikings is a fascinating and complex story.

### Output:
Non-fiction.