Reinforce in example sentence
The frustrated viewer may be forgiven for concluding either that neither producer nor screenwriter had read anything relevant beyond a short encyclopaedia article or two (though, doubtless, both looked at many an illustration of the time: costumes and sets are largely accurate) or that both deliberately chose to reinforce the stereotypes to which the ignorant subscribe (Parliamentarians were dull, bigotted fools; Royalists were noble and brave; etc., etc., etc.).