This paper concerns the presentation of two projects that aim to make available an online archive of 4,000 original private letters, mainly having in mind research in Linguistics (Corpus Linguistics, Historical Linguistics, Pragmatics, Sociolinguistics, General Linguistics), History and Sociology. Our corpus is prepared for each research area and provides a diachronic archive of the Portuguese language. Projects CARDS and FLY have the main goal of making available an online electronic edition of each letter, which is completely open source, searchable and available. Users can search for an individual letter, a text by type, a group of letters by year or even the whole archive as a corpus for research or other purposes. The means of corpus presentation is a multimodal framework, since it joins together both the manuscript's image and the written text: the letter's material representation in facsimile and the letter's digital transcription. This editing method allows for the possibility of creating an annotated corpus where the textual unity is not lost.