The portolan chart is of the same tradition as the isolario, and
many of the portolan atlases made by the Oliva family and other chart makers of
the period include an isolario at the end. This fine example has only
charts. Portolan charts were used by mariners well into the seventeenth century,
but there was also a demand for richly decorated versions among the enlightened
wealthy. One can assume that the present atlas was meant for this market. Joan
Oliva was the most prolific member of a large family of Catalan chart makers,
one branch of which had settled in Messina (Sicily) some time before 1550.
Charts signed by at least sixteen members of the Oliva family are recorded, with
dates between 1538 and 1673.