Every essay should be based upon personal research and analysis. Any factual material or ideas taken from other sources must be acknowledged using a reference, unless it is common knowledge (e.g., World War II continued from 1939 until 1945).
Referencing is a standardised way of acknowledging the sources of information and ideas that you have used in your document. You must reference any information you have taken from both primary and modern sources. There are two types of quotations:
A direct quote is a word-for-word extract taken from either a primary or a secondary source.
An indirect quote is when you have used an idea or opinion from a source but have paraphrased (summarised) it into your own words. This is extremely useful to highlight the main idea of a source and is usually a better method of showing information than using a direct quotation.