Old man in article on several Tory leaders' history? (3,4)

'history?' is the definition.
(thesaurus)

'old man in article on several tory leaders'' is the wordplay.
'old man' becomes 'pa' (both can mean someone's father).
'in' means one lot of letters goes inside another.
'article' becomes 'the' (the definite article in English).
'on' means one lot of letters go next to another.
'leaders'' indicates taking the first letters (I've seen 'leaders' mean this).
The first letters of 'several tory' is 'st'.
'the'+'st'='thest'
'pa' going into 'thest' is 'THE PAST'.