The House of York were descendants of the Mortimer family. The Mortimer History Society website has many lectures about this family and their connections, including some of the talks from a joint Richard III Society/MHS conference in 2019.
Many of the Churches Conservation Trust lectures cover medieval topics, including humorous marginal illustrations in manuscripts; cadaver memorials; saints in the medieval church; the meaning of satirical carvings; a history of stained glass; historical graffiti; and Purgatory.
The British Archaeological Association’s online lecture topics include the medieval stained glass at Long Melford and at Westminster Abbey; the fabric accounts of St Stephen’s chapel, Westminster; church architecture and medieval bridges.
The York Ideas Youtube channel includes a lecture on medieval hygiene.