this might be a good resource for you

http://www.maa.org/news/on-this-day 

this could be a good starting point for ideas for the history lectures if you need some more ideas and possibly references

http://www.storyofmathematics.com/

University of Oxford - History of Mathematics

https://www.maths.ox.ac.uk/groups/history-mathematics 

TedTalk 

https://www.ted.com/talks/jean_baptiste_michel_the_mathematics_of_history 

Cambridge University 

https://www.maths.cam.ac.uk/about/history