Their initial reception was unpromising: the MacLeods and MacDonalds advised Charles to return to France, but were persuaded by the commitment of the powerful and influential Donald Cameron of Lochiel to join them. Charles now had a force of about 1,000 and on 19 August launched the rebellion by raising the Royal Standard at Glenfinnan. The Jacobites advanced towards Edinburgh, reaching Perth on 4 September where they were joined by more sympathisers, among them Lord George Murray. Murray was an experienced soldier pardoned by the government for his role in the 1715 and 1719 risings; he replaced O'Sullivan as commander due to his better understanding of Highland culture and spent the next week re-organising it. The senior government officer in Scotland, Lord President Duncan Forbes received confirmation of the landing on 9 August, which he forwarded to London. His military commander Sir John Cope had only 3,000 mostly untrained recruits and initially could do little to suppress the rebellion. Forbes instead relied on his personal relationships to keep people loyal and though unsuccessful with Lochiel, Murray and Lord Lovat, many others stayed on the sidelines as a result.

Based on the above article, answer a question. Who served first as commander, Murray or O'Sullivan?
O'Sullivan