How were the circles drawn?

[Jorge_Stolfi]

Just to answer the first question - yes, compasses were certainly being used to draw circles in manuscripts by the fifteenth century.

Thanks! But were they used to draw circles in ink (as opposed to pencil or dry-point)? 

if so, how did they do it?  With a metal attachment similar to the "modern" one?  Or with a quill, attached to the compass in some way?

All the best, --jorge