So the Speculum, 44a.
The chronicle of the xxiv.

generals and Mark of Lisbon (Diola's ed., t.i., p.

82) holds also to 1217, so that, though not definitely established, it would appear that this date should be accepted until further information.

Starting from slightly different premises, the learned editors of the _Analecta_ arrive at the same conclusion (t.ii., pp.

25-36).