The archaeological record suggests that during the first Out of Africa dispersal, Western Europe stayed at the limit of the human “Oekumen” for almost 1 million years. The earliest evidence of hominin diffusion out of Africa is dated to 2.1. million years in Eurasia (Levant and China) (Lepré et al. 2011; Pappu et al. 2011; Beyene et al. 2013; Zhu et al., 2018). Hominins reached the gateway of Europe, specifically the southern Caucasus, around 1.8 million years ago (Mgeladze et al. 2011), but the first human occupations of Western Europe are not documented until 1.2-1-4 million years ago (i.e. Arzarello et al., 2007; Moyano et al., 2010). We consider three hypotheses to explain this chrono-spatial pattern: i) the current pattern may be the result of taphonomic bias, ii) the climatic, geographical or environmental conditions of Western Europe may have hindered the expansion of hominin populations, and iii) specific cognitive capabilities may have been necessary for hominins to successfully occupy this mid-latitude area. The Early and Middle Pleistocene archaeological record is relatively sparse and fragmented, and has very low temporal resolution. Consequently, the colonization process is generally not well understood, and the complex interplay between subsistence behaviour, technology and hominin ecology is difficult to trace and reconstruct. In this study, we present a simulation-based approach to formalize and test the above hypotheses while integrating available archaeological and climatic data. To deepen our understanding of this process, we are designing a large-scale Agent-Based Model (ABM) that will integrate the impact of ecological and geographical barriers on dispersal and interactions between hominin groups. The chronological and spatial framework of the model will represent Western Europe and part of (Western?) Asia between 1.3 million years and 500 ka years ago (Marine Isotope Stage 12, a deep glacial event considered as a threshold). To incorporate a wide set of dynamics and parameters, a series of detailed ABMs on smaller scales will be developed. Specifically, three models will be used to analyse different aspects of the first populations in Western Europe. To define the scale and resolution and the entities and interaction rules we follow the ARDI protocol which makes it possible to involve a greater number of different specialists in the co-construction of the models (Etienne et al., 2011). The first model aims to reconstruct evolving European ecosystems over time and hominin responses to them, and consists of two modules: one representing the reconstructed ecosystems, and the other simulating population dispersal as a function of the ecosystem dynamics. The second model will analyse how hominin subsistence and mobility patterns adapted to different climatic conditions within ecosystems (i.e., glacial vs. interglacial). Initially, the model will simulate a single group subsisting in three ideal environments corresponding to different latitudes. Subsequently, complexity will be increased by introducing resource dynamics among groups and a greater environmental variability. The third model has dual objectives: to understand hominin interaction networks and the spread of ideas, and to analyse how environmental variability may have influenced technological adaptations. This model will utilize agent-based modelling along with tools from social network analysis to analyse dispersion of innovations within them. The integration of the three sub-models into the large-scale model will be done in three phases, gradually increasing its complexity. The first phase will involve a simple reaction-diffusion model in which population dispersion is a function of population growth. The second phase will build upon this by incorporating the range of variability observed in the subsistence and mobility sub-model. Finally, aspects of group interaction and transmission of ideas will be included. Not only will the models be interconnected, but the information collected and generated by archaeologists working with different archaeological remains within our project (such as pollen, raw materials, isotopes or lithics) will also be used in the modelling cycle for the parametrization or validation of the models. Our comprehensive simulation-based approach, which includes archaeological and climatic data and which also will integrate ecological, geographical and social factors, aims to shed light on the complex interplay of variables that influenced the colonization of Western Europe during the Early and Middle Pleistocene. Through this endeavour, we also seek to establish the limits of applicability of these methods to the study of the Early and Middle Pleistocene and develop tools that help overcome some of these limitations. Eventually, we also hope to contribute to a deeper understanding of these early stages of human evolution.