Under the leadership of the Goths, a series of major invasions of the Roman empire were launched by a grand coalition of lower Danubian tribes from c. 238 onwards. The participation of the Bastarnae in these is likely but largely unspecified, due to Zosimus' and other chroniclers' tendency to lump all these tribes under the general term "Scythians" – meaning all the inhabitants of Scythia, rather than the specific Iranic-speaking people called the Scythians. Thus, in 250–251, the Bastarnae were probably involved in the Gothic and Sarmatian invasions which culminated in the Roman defeat at the Battle of Abrittus and the slaying of Emperor Decius (251). This disaster was the start of the Third Century Crisis of the Roman Empire, a period of military and economic chaos. At this critical moment, the Roman army was crippled by the outbreak of a second smallpox pandemic, the plague of Cyprian (251–70). The effects are described by Zosimus as even worse than the earlier Antonine plague (166–180), which probably killed 15–30% of the empire's inhabitants.