Adriano Cappelli's «Lexicon abbreviaturarum» is one of the most renowned collections of abbreviations. In a very successful crowd sourcing project, Ad fontes (www.adfontes.uzh.ch), an e-learning platform at the University of Zurich, has digitised, systematised and made freely available all 14'357 abbreviations included in the Cappelli. The specifically designed search interface not only allows to search by the readable letters, with the possiblity to set wildcards for non-identifiable characters, but also to search by visual criteria.