542 THE SOVEREIGNTY OF THE SEA 



early at least as the seventh century. 1 The thalweg or mid- 

 channel was not infrequently a boundary between contiguous 

 states, and it was not a great step to transfer its application 

 in theory from wide rivers and estuaries to intervening seas. 

 In this way the mid-line in the sea lying between the coasts 

 of two states was held to be the boundary of their respective 

 maritime jurisdiction or sovereignty. The whole extent of a 

 sea stretching between territories belonging to the same state, 

 however far apart these territories might be, was looked upon 

 as being under the sovereignty of that state. This principle, 

 therefore, covered most extensive claims to maritime dominion, 

 since it left hardly any part of the sea unappropriated. The 

 mid -line as an international boundary was in the case of 

 narrow seas logically derived from the tenets of the Italian 

 lawyers, but there are grounds for believing that it may have 

 been much older. An ancient example of its use in a limited 

 way is to be found in King Cnut's charter, in 1023, granting 

 the port of Sandwich, in Kent, to the Church at Canterbury, 

 by which certain rights of wreck up to the middle of the sea 

 were conferred on the monks. After mentioning "the great 

 sea without the port," it provided that half of whatever was 

 found " on this side of the middle of the sea," and brought to 

 Sandwich, should belong to the monks and half to the finder. 2 

 Cnut's charter cannot be taken as expressing any direct claim 

 to jurisdiction to the middle line, but as wreck was a prerog- 

 ative of the crown and this is the first grant of it the limit 

 assigned seems to imply a differentiation of authority. More 

 pertinent is the statement in the Mirror of Justice, a law-book 

 written about the end of the thirteenth century, and attributed 

 to Andrew Horn, who was Chamberlain of London in the reign 

 of Edward II., that the king's sovereign jurisdiction extended 

 as far as the middle line of the sea surrounding the land. 3 



1 In the definitions of the boundaries of lands and fisheries in Anglo-Saxon 

 charters such descriptions occur as "up midne streame," "ut on Temese oS midne 

 stream," "up midne streame by halfen streame," &c. Birch, Cartularium Saxonicum. 



- " Quicquid etiam ex hac parte medietatis maris inventum et dilatum ad Sand- 

 wic fuerit sive sit vestimentum sive rete arma ferrum aurum argentum, medietas 

 mouachorum erit, alia pars remanebit inventoribus." Kemble, Codex Diplomaticus 

 jEvi Saxonici, iv. 21. 



3 Le Mirroir des Justices, c. iii., "la sovereine seignurie de tote la terre jeqes 

 el miluieu fil de la meer environ la terre." 



