He had it from Governor Calvert that he might dwell on in Kent Island, trading from there, but only under license from the Lord Proprietor and as an inhabitant of Maryland, not of Virginia.

Claiborne, with the Assembly at Jamestown secretly on his side, resisted this interference with his rights, and, as he continued to trade with a high hand, he soon fell under suspicion of stirring up the Indians against the Marylanders.
At the time, this quarrel rang loud through Maryland and Virginia, and even echoed across the Atlantic.

Leonard Calvert had a trading-boat of Claiborne's seized in the Patuxent River.

Thereupon Claiborne's men, with the shallop Cockatrice, in retaliation attacked Maryland pinnaces and lost both their lives and their boat.

For several years Maryland and Kent Island continued intermittently to make petty war on each other.
At last, in 1638, Calvert took the island by main force and hanged for piracy a captain of Claiborne's.