After I’d posted yesterday’s quotation, from Brossard (trans. Mascall)’s A Booke of the Arte and Maner… (1575), I took another look at The Customs of London / Arnold’s Chronicles (1502), which is one of the earliest known English language texts that mentions fruit tree management methods. Sure enough, there was a section on ‘family‘ fruit tree grafting here as well:
“Yf thou will greff dyvers frutis upon one stok that hath as many braunchis as thou will have graffes on and in every braunche sett a graf in maner and fourme as said before, and evermore chese thy graf on the south syde of the tree that berith it and nexte the toppe yf thou may and thou mayst gref dyvers frutis on oon clyfte but non of them may be thykkar than odur as thy reson will telle thee in thy workyng.“
Quick recap / translation: you can graft one scion per branch, take scions from high up on the south side of the original tree, and you can set more than one scion in each cleft in the stock as long as they’re all of a similar thickness.
Again though, the idea of a multiple-variety tree is clearly a well-established method for growing multiple types of a particular fruit in a reduced amount of space.