As part of the Peter Cornelius festival in Mainz, Germany, to celebrate the bicentenary of the composer's birth (and 150 years since his death), there will be an exhibition about him, and also an international conference about opera in Germany in the mid 19th century. Details here (https://mugemir.de/wp-content/uploads/2024/04/Flyer_Cornelius_Tagung_MZ.pdf). To round off the conference, there will be a performance of Cornelius's opera "Gunlöd" on 25 May.
It would be great to be able to access this article on Cornelius:
https://www.jstor.org/stable/959852
This study also looks interesting:
https://ia800906.us.archive.org/5/items/operasofpetercor00lawt/operasofpetercor00lawt.pdf