When a man sells a rent of assize due from a city tenement of which someone else is the tenant, the purchaser cannot have full seisin delivered without [the acquiescence of] the tenant of the property from which the rent issues. So, when recognizance of the deed of transfer is made in court before the bailiffs, in the presence of the purchaser and vendor, the purchaser may request that the tenant immediately be summoned to court. If the tenant comes, the bailiffs are to ask him whether the tenement was the property of the vendor or owed to the vendor the said rent. If the tenant acknowledges this, he is to be advised by the bailiffs that the rent should henceforth be paid to the purchaser, so that the latter have the same lordship over the rent that the vendor had, including the power to distrain for [arrears of] the rent. By reason of this acknowledgement, the purchaser may in any plea (if necessary) assert that he made distraint on his own property, and the tenant may not deny that rent is due from the property to the purchaser. However, if when the tenant comes he denies that any rent issues from the tenement to the vendor, the purchaser may request an inquest into the matter. If this finds that the tenement was, at the time of the sale, within the lordship of the vendor, the tenant is to be instructed to pay the rent to the purchaser henceforth; if it does not, the tenant may leave free of any obligation. If the tenant refuses to come to court to perform his duty, the bailiffs have full power to distrain on the tenant (if the purchaser so requests) from day to day by anything distrainable at the tenement in question or other tenements in the city [held by the tenant], until he comes. If, after the tenant's denial of the vendor's lordship, an inquest is called but the tenant defaults [in participating], the inquest may nonetheless proceed and a verdict may be issued on the matter. The same procedure is to apply with regard to rents bequeathed to any individual or to be sold by the executor. If a [sub-]bailiff reports to a court, three days running, that he can find nothing in the city by which to distrain the tenant, then the bailiffs may give the purchaser leave to try to make distraints. If the tenant, after acknowledging the rent due, sells or alienates the tenement in question, he must join with the new tenant in repeating the transfer of the obligation to the latter. No essoins are allowed to any party in the aforesaid process.
[When the tenant (who, as can be seen, might well be the owner of the physical property) made his acknowledgement to the owner of the rent this was called "attorning" himself to his new "lord" (i.e. the individual to whom an obligation was due through tenancy of the property).]