Mary Renault, eh?  

Snap.

I think I must have been in my mid to late teens when I discovered her books.

I think my personal favourites would be 'The Mask of Apollo' and 'The Last of the The Wine'.  But I have read The Bull From the Sea, and The King Must Die.  And one of the Alexander series - The Persian Boy.

Then there were the other historical romancers - I still have Mary Stewart's Arthurian books, 'The Crystal Cave (which I think I first encountered when I was only about 7!)', 'The Hollow Hills', and 'The Wicked Day', on my shelf; alongside Rosemary Sutcliff's take on the Arthur story, "Sword at Sunset".

I greatly enjoyed Georgette Heyer's "The Spanish Bride" and "An Infamous Army".  And then there was the C S Forester 'Hornblower' series.

Mary Stewart is another of my favourites. She acknowledges Mary Renault as an influence. One of her characters mentions reading Renault before a trip to Greece but I can't remember offhand which novel this was in.
Her description of the young Merlin growing up at his grandfather's court with no earthly father and a reputed supernatural conception has distinct parallels with Mary Renault's description of that of Theseus.