The tradition as embodied in Muirchu represents him as remaining at Auxerre till his departure for Ireland, and though it might easily be erroneous, it is, so far as it goes, against the possible theory that Patrick’s sojourn at Lérins is to be placed after his visit to Britain. But we have another piece of evidence which seems to me decisive, namely, one of the so-called Dicta Patricii. See [Excursus 6], ad fin.
The argument for placing the sojourn at Lérins before the return to Britain may be summed up thus: (1) the reminiscence of Patrick’s wanderings almost certainly refers to his wanderings after his escape, and there can hardly be any doubt that the “islands in the Tyrrhenian Sea” mean the islands of Lérins, in view of the definite tradition (Tírechán, 302₂₄) that he stayed in the insola Aralanensis; (2) this date for the retreat to Lérins supplies the much-needed explanation of his delay in returning home.
The following chronology, then, may be a rough approximation:—
A.D. 411/2 escape from his ship-companions;
A.D. 411/2-414/5 at Lérins;
A.D. 414/5 returns to Britain;
A.D. 415/6 goes to Auxerre;
A.D. 416-8 is ordained by Amator;
A.D. 418 death of Amator, who is succeeded by Germanus;
A.D. 418-432 Patrick remains at Auxerre, as deacon;