What does Gertrude mean?
From Germanic 'ger' (spear) and 'thrud' (strength), so 'strong spear'. The 'spear' element is a weapon of war rather than 'warrior' outright, but the martial sense is well established.
What does Hilda mean?
Built on the Germanic element 'hild' meaning 'battle'. It began as a short form of longer names such as Hildegard and Brunhild before becoming an independent name.