dɪvˈɛləpmənts ɪn fˈeɪshˈɑːɹdənd ˈɑːɹmɚɹ ɪnðə lˈeɪt nˈaɪntiːnθ ænd ˈɜːli tə mˈɪdtwˈɛntiəθ sˈɛntʃɚɹiz ɹᵻvˈiːld ðæt sˈʌtʃ ˈɑːɹmɚ wʌz lˈɛs ɪfˈɛktɪv ɐɡˈɛnst ɡlˈænsɪŋ oʊblˈiːk ˈɪmpækts.
Developments in face-hardened armour in the late nineteenth and early to mid-twentieth centuries revealed that such armour was less effective against glancing oblique impacts.