where does the saying achilles heel come from
Achilles' heel In Greek mythology, when Achilles was a baby, it was foretold that he would die young. To prevent his death, his mother Thetis took Achilles to the River Styx, which was supposed to offer powers of invulnerability, and dipped his body into the water; however, as Thetis held Achilles by the heel, his heel was not washed over by the water of the magical river. Achilles grew up to be a man of war who survived many great battles. One day, a poisonous arrow shot at him was lodged in his heel, killing him shortly afterwards.
Thorn in the flesh The phrase "thorn in the flesh" continues to be used as a metaphor for "a source of continual annoyance or trouble."[14] It is synonymous with the phrase "thorn in the side," which is also of biblical origin, based on the description in Numbers 33:55.[14] As an example usage, the Oxford English Dictionary cites E. M. Forster's 1924 novel A Passage to India, in which Nawab Bahadur says, "I can be a thorn in Mr. Turton's flesh, and if he asks me I accept the invitation."[15]