A thematic essay is an essay in which they give a theme to write about. For example there are themes like Geography, Wars, Turning points, etc.

There are many good Introductions to a thematic essay for example

Throughout global history (give the name of your theme) has/ have a major impact on people. (give the name of your theme) is are (give the meaning of you’re theme. The importance of give the name of your theme) can be seen in the example of (give examples of your theme). (Introduction)

The examples of (give examples of your theme) and clearly demonstrates (give me the name of your theme). (Give an example of your theme) is important (explain why your example is important). (Give an example of your theme) is important (explain why your example is important). Conclusion