Henry was the grandfather of William Sinclair, 1st Earl of Caithness, the builder of Rosslyn Chapel near Edinburgh, Scotland. The authors Robert Lomas and Christopher Knight believe some carvings in the chapel to be ears of New World corn or maize. This crop was unknown in Europe at the time of the chapel's construction, and was not cultivated there until several hundred years later. Knight and Lomas view these carvings as evidence supporting the idea that Henry Sinclair traveled to the Americas well before Columbus. In their book they discuss meeting with the wife of the botanist Adrian Dyer and explain that Dyer's wife told them that Dyer agreed that the image thought to be maize was accurate. In fact Dyer found only one identifiable plant among the botanical carvings and instead suggested that the "maize" and "aloe" were stylized wooden patterns, only coincidentally looking like real plants. Specialists in medieval architecture interpret the carvings as stylised depictions of wheat, strawberries, or lilies.