Seattle University is making plans for a new art museum, thanks to a gift of a $300 million art collection and $25 million in seed money from a donor, the university trustees announced on Wednesday. The donation — by Richard Hedreen, a real estate developer — is the largest gift in the history of the university, a Jesuit institution founded in 1891, the trustees said in a statement. Hedreen is donating his entire collection, which has more than 200 works of art dating from the 15th century to today, including art by Thomas Gainsborough, Lucian Freud and Amy Sherald.