The network “Developing Quality in Mathematics Education II” will be a continuation of the associated project “Developing Quality in Mathematics Education”. It will be an extension of the very productive and transferable results attained so far, and an expansion from four to twelve participating countries. Because we have in each country groups consisting of universities, teacher education institutions and schools, a special feature of this project will be the strong connection between theory and practice and between the research and development of mathematics education. Cross-cultural cooperation and exchange of ideas, materials, teachers and pupils will be continued by developing quality in mathematics education, especially in the area of mathematical modelling. The quality and application of the developed learning materials will also be guaranteed by using, comparing and modifying them in twelve different countries. This comparison will lead to an agreement about contents of mathematical learning and teaching in twelve European countries. Thus it is hoped to establish a “European Curriculum for the teaching and learning of mathematics” in the 21^st century. Using the available technology of today (for example the planned communication platform) we hope to provide far reaching and exciting possibilities for sharing ideas and methods and exchanging materials, including video-sequences, to get a better understanding of the development of epistemological aspects of mathematics education. An exciting, extraordinary and substantial consequence of this project will be that the community of mathematics educators in Europe will be able to expand and share their professional relations and collaboration opportunities.