Dumpor's Case holds, according to the syllabus in Sir Edward Coke's Reports (4 Coke 119b) that "a condition in a lease that the lessee or his assigns shall not alien without the special license of the lessor, is determined by an alienation by licence, and no subsequent alienation is a breach of condition, nor does it give a right of entry to the lessor." The same case more properly titled "Dumpor v Symms" (Coke) or "Dumper v Syms" is reported by Sir George Croke (Croke's Eliz. 815) The head note there reads: "On a proviso that a lessee and his assigns shall not alien without licence, if the lessor give licence, the condition is entirely destroyed and the assignee may afterwards assign or demise the whole or any part of the term without licence; but otherwise a devise of the term would have been a breach of the condition."
Robert S. Macfarlane,
Notes and Comments,
Dumpor's Case: Its Status,
Wash. L. & Rev.
Available at: https://digitalcommons.law.uw.edu/wlr/vol1/iss1/5