'Given to understand' as a model for the indirect/recipient passive in English?

The advent in English of passives like 'he was given a book' has long been a source of interest. Such passives, in which what is traditionally analysed as an indirect object is passivized, are not found in Old English. Macleod, Anagnostopoulou, Mertyris & Sevdali (2023) suggest that they may have developed as an extension of sentences like 'he was given to understand', with what was originally an indirect object being reanalysed as a direct object because of the rather opaque nature of 'given to understand'. A corpus-based study rules this construction out as a model for the new passive, which is found two hundred years earlier than given to understand.