Weave is a bottom-up cross-European initiative developed by European research funders – and embedded in Science Europe – to support excellent European collaborative research projects across national and regional borders. Based on the Lead Agency Principle, Weave aims to simplify the submission and selection procedure of collaborative project proposals: a European team of researchers from two to three European countries or regions that have signed the Weave initiative, submits their joint project proposal to only one research funder (Lead Agency) who is responsible for the entire administrative procedure and scientific evaluation. Each research funder involved is as such responsible for the payment of its own researchers (i.e. researchers eligible for funding from this research funder). Since Weave will enable bilateral as well as trilateral scientific cooperation within Europe, it will contribute to the realisation of the European Research Area (ERA).