How important is knowledge of historical context when answering exam questions?

Many exam boards, as part of their assessment objectives, require students to discuss literary texts with their historical/social context in mind - however it should not dominate an answer as relaying historical knowledge is more descriptive rather than analytical and higher grades are generally obtained through perceptive analysis rather than through knowledge alone. Ideally, a candidate should incorporate historical context into their analysis of the text.
For example, when answering a question on Othello, rather than simply acknowledging that Othello's character is black and Shakespeare wrote in dangerously racist times, consider Othello's race in relation to depictions of him (e.g. looking at animal imagery and how this relates to the dehumanisation of ethnic minorities in Shakespeare's time). Also, considering whether texts conform to or challenge their times can be helpful in terms of demonstrating analysis as opposed to just stating facts.