This chapter discusses from three perspectives the stages of the hybridity of writing systems in the period of the formation of various alphabets as well as their adaptations to the requirements of specific languages. Firstly, the chapter draws attention to the role of borrowings and intersystemic influences at the early stage of the formation of the ‘grand’ alphabets, including the Greek, Latin Cyrillic and Arabic alphabets. These are forms of writing of a long tradition, which later became the basis for numerous national alphabets. Adaptations which adjust a certain alphabetic system (the base alphabet) to the needs of writing the phones of a different language constitute the second – narrower – perspective on contacts between alphabets and the transformations within them. The reflections in this part are exemplified by references to the Latin alphabet in its Polish edition. The chapter then focuses on the narrowest perspective, drawing readers’ attention to alphabet adaptations that did not achieve the status of national writing. This is exemplified by two – entirely different – models of adaptation, comprising the Polish graždanka (Polish Cyrillic alphabet) and the Polish and Belarusian Arabic-graphic writing (aljamiado). Additionally, the author briefly discusses Polish texts written in the Armenian alphabet.