CLARIAH-DE is the merger of the research infrastructure networks CLARIN-D and DARIAH-DE. CLARIAH-DE is merging the two established research infrastructures over the course of two years (2019-2021). Thus, academic endeavours of researchers from the humanities and cultural sciences who work with complex digital tools and special data repositories shall be substantially facilitated. Both research infrastructures pursue goals directly connected to the scholarly primitives - discovering, annotating, comparing, referring, sampling, illustrating and representing - as they provide services and resources for them.

A large work package (WP4) is devoted to the harmonisation of the CLARIN-D and DARIAH-DE technical infrastructures. Infrastructure has to be seen both as basic or generic components like AAI, PIDs, monitoring, collaboration platforms but also as research oriented services, like the CLARIN Federated Content Search, the DARIAH Collection Registry or a GeoBrowser. Our work is based on previous cooperation, for instance the joint Technical Advisory Board (TAB), and preliminary integrative endeavours in recent years.

But despite well established communication processes such as the TAB it doesn't come as surprise that the practical merger leads to considerable challenges. CLARIN-D and DARIAH-DE have different disciplinary traditions, and have thus developed different technologies, tools, services and processes that now have to complement each other. The consolidation, however, is not straightforward, as is the case, in particular, with the merging of the three search and retrieval tools: Generic Search, Federated Content Search and Virtual Language Observatory. Consolidation often also requires the harmonisation of standards and interfaces (resource metadata, interchange formats). In other areas, such as Authentication and Authorization Infrastructure (AAI), we already found a solution based on CLARIN's and DARIAH's existing AAI-approaches. The work package is complemented by a technology watch that goes beyond CLARIN and DARIAH and tries to incorporate the most important developments in the field into its own plans wherever possible.

Beyond this we must also consider the European level. Both CLARIN-D and DARIAH-DE are contributing partners to the ERICs and limitations that have to be considered in the merger of two national infrastructures come with this interwovenness. CLARIAH-DE is directly involved in European development through its two partners. CLARIN-D is part of CLARIN - European Research Infrastructure for Language Resources and Technology and DARIAH-DE is the German partner of Digital Research Infrastructure for the Arts and Humanities (DARIAH-EU).

In addition, and as research driven infrastructures, the community perspective is possibly most important, joining the picture of interdependencies: both CLARIN-D and DARIAH-DE are well established with users and dissemination activities which contributed to the level of trust researchers have in them. Trust is a very important and delicate asset which has to be taken into consideration at all stages of the merger process.

The paper presents some of our experiences in the merger process. We try to reflect not only on an infrastructural level but also involve the community perspective. We want to use this opportunity to collect feedback particularly from the European partners and projects and are interested in useful experiences from other initiatives.