Who wrote ofer fifity plays and was considered by some to be the leading french playwright of his day?

The playwright you're thinking of is Pierre Corneille. He wrote over 50 plays and was considered by many to be the leading French playwright of his day.

Some of his most famous works include:

* Le Cid (The Cid)

* Horace

* Cinna

* Polyeucte

* Andromaque

* Mérope

Corneille's plays were known for their strong characters, powerful language, and complex plots. He was a master of tragedy and his work helped to establish French classical theatre.