Robert Havell, a renowned London engraver, was engaged by Audubon to reproduce the Birds of America. The portfolio, comprised of 435 hand colored engravings, took twelve years, from 1826 to 1838, to complete. Audubon sold 175 subscriptions to Birds of America, each of which was priced at the cost of a substantial home at the time, $1,000. The edition was published on sheets measuring 26 inches by 39 inches, called double elephant by the printing trade. The resulting engravings, depicting each subject in its actual size, are among the largest ever made. Still, Audubon often altered the larger birds' natural postures, creatively composing the figure to fit within the dimensions of the sheet. A maximum of 200 complete sets of Birds of America were made. Of these, more than 100 are intact in library and museum collections worldwide. In the more than 150 years since they were first printed by Havell, few of the sets have been broken or made available for sale.