Reading Scholem's historical writings along with his letters to Benjamin, we begin to understand the depth of his reaction to the latter's leftward turn.

Could you please clarify to me why there is an apostrophe in the word "latter". Does this mean the same as to his (Benjamin's) latter leftward turn. To tell the truth I am not familiar with the usage of the apostrophe in adjectives. Is it standard in English? Based on the same pattern we can write/tell: John broke the window. I am really upset by terrible's behaviour (by his bad behaviour) which is probably nonsense.

Reading Scholem's historical writings along with his letters to Benjamin, we begin to understand the depth of his reaction to the latter's leftward turn.

Could you please clarify to me why there is an apostrophe in the word "latter". Does this mean the same as to his (Benjamin's) latter leftward turn? To tell the truth I am not familiar with the usage of the apostrophe in adjectives. Is it standard in English? Based on the same pattern we can write/tell: John broke the window. I am really upset by terrible's behaviour (by his bad behaviour) which is probably nonsense.