1707, J[ohn] Mortimer, The Whole Art of Husbandry; or, The Way of Managing and Improving of Land.[…], 2nd edition, London: […] J[ohn] H[umphreys] for H[enry] Mortlock[…], and J[onathan] Robinson[…], published 1708, →OCLC:
The shafts of a wagon; the arms of wood between which the last horse is placed.]
1868, Elihu Burritt, Walks in the Black Country and its green border-land, page 310:
As for one of the great four-wheeled wagons used here, thilled instead of poled, an American farmer would hardly think of dragging it up a hill empty with a single horse.