During my PhD I came across the Mathematics Genealogy Project: an attempt to explore the family tree of mathematicians going back hundreds and hundreds of years.
Maybe you have something similar in your discipline or maybe you have a general appreciation that you are part of a tradition: your work continues to build on the past ideas, research and achievements of other dedicated humans. It’s nice to think about and can be very helpful to reflect on where your work comes from as you get ready for the viva.
Don’t forget you have academic siblings today too. There are many people around you who can help you to get ready for your viva, either by helping you practically, sharing information or simply being there. Make sure you ask for support from people who are really well-placed to help.