Although the Young's modulus is undoubtedly one of the most important mechanical characteristics of bone, its proper determination in the course of quasi-static mechanical tests is still a matter of debate. In order to shed some light onto this issue, the present Master's thesis is concerned with the accurate determination of elastic properties of bovine cortical bone at millimeter-length-scale. To achieve this goal, a set of cylindrical samples with diameters of 7 mm and heights of 12 mm was extracted from an 18-month-old bovine femur. At first, a representative specimen was saturated with distilled water, whereby its weight gain (corresponding to the filling of vascular pores) was constantly measured, and this allowed for computation of the vascular porosity as vas = 7.9%. Subsequently, a set of uniaxial quasi-static unloading experiments with a displacement level of 0.125 mm and a displacement rate of 0.031 mm/s, gave access to the longitudinal macroscopic Young's modulus as Eunloading = 23.2 1.2 GPa. As a next step, extracellular mass densities of 22 bovine tibia samples were taken from [Lees et al., 1979] and entered a multi-step homogenization scheme for bone as a hierarchical transversely isotropic material, as developed in [Morin and Hellmich, 2014]. Numerical evaluation of the latter, while taking into account the vascular porosity from the wetting and weighing test, delivered a full stiffness tensors of bovine cortical bone at the macroscopic level. The Young's modulus derived from this stiffness tensor and amounting to Ehiercarchy = 22.5 2.1 GPa, reveals a very good agreement of the unloading tests and the previously extensively validated model. This elucidates unloading as the key feature to retrieve a "true" elastic modulus from a quasi-static test. Apart from this findings, which were recently submitted to the Journal of Biomechanics, a detailed sample characterization as well as comprehensive results of the quasi-static mechanical tests, and a brief outlook to the future are given as conclusion of the thesis.