In current business practice, an integrated approach to business and IT is indispensable. In many enterprises, however, such an integrated view of the entire enterprise is still far from reality. To deal with these challenges, an integrated view of the enterprise is needed, enabling impact and change analysis covering all relevant aspects. This need sparked the development of the ArchiMate language. This paper is concerned with documenting some of the key design decisions and design principles underlying the ArchiMate language.