The Filiki Eteria or Society of Friends was founded in 1814 in Odessa, Russia. It was the most important Greek secret society of the period, playing a key role in the preparation and, above all, the launching of the Revolution of 1821. A landmark in its activities was the transferral of its headquarters to Istanbul in late 1817, a move that resulted in increased membership and improved finances, and, by extension, increased the capabilities of the Society.