The existence of three surveys at twenty-year intervals in the second half of the fifteenth century invites analysis of the income provided by their estate for the wealthiest family in late-medieval Cornwall. It must again be stressed that the surveys do not provide the whole story: we have already seen that there were some minor Cornish lands which do not appear in these surveys; even in the manors listed here there were other revenues (shown in the manorial accounts) in addition to the rents, such as profits from the manorial courts and toll of tin; there were probably direct interests in the tinning industry too; and there were also the lands in Devon, Dorset and elsewhere.

Therefore the actual income of the family will have been very different from the estate revenues shown here. Indeed, if John Arundell's alleged yearly income of £2,000 in 1451 is correct, then the rents of the Cornish manors surveyed in 1451-64 provided little more than a tenth of his income; and these amounts are gross income and do not generally include outgoing payments. £200 yearly would have been an average income for a knight in the earlier fifteenth century; so we should expect that of the Arundells to have been considerably higher, if only to have given rise to the legends about this John Arundell and his grandfather, ‘the Magnificent’.

What follows is only a preliminary analysis, since too many of the total sums are uncertain. Moreover, these surveys record only what the lords expected to collect in rents; the sums actually received varied from year to year according to the capacity of individual tenants to pay. The table shows that the overall revenues expected were stable, showing a slight rise from 1460 to 1499; only Treloy fell significantly in that period. Within that general picture, however, there were minor differences. Most manors were extremely stable throughout the forty years: Bodwannick (rise of nearly £2), Connerton, Enniscaven, Kennall, Lanhadron (judging by the two figures only), Tregarne and Winnington are notable; probably Mitchell as well, if the full figure for 1463 were available. Those manors which showed a significant rise in our documents were either towns (St Columb and Truro Vean), or those where demesne farming was abandoned (Carminow and Trembleath).