Rubuta ci gaba ga wannan sakin layi - Robert Umfraville ya kasance aikin soja ne. Marubucin tarihin John Hardyng (wanda ya shiga aikin Umfraville a wani lokaci tsakanin 1402 da 1403) ya ba da rahoton cewa Umfraville ya yi yaƙi a yakin Otterburn a 1388, a matsayin wani ɓangare na ƙungiyar Henry Hotspur (ɗan Earl na Northumberland). Wannan, in ji Hardyng, an bi shi da na farko daga cikin hare-haren kan iyaka da Umfraville ya jagoranci a Scotland a 1390. Wadannan sun ci gaba da bin Sarki Richard II, kuma mai yiwuwa ya shiga cikin yakin Homildon Hill
a shekara ta 1402. A zahiri, duk da canjin tsarin mulki na 1399, ayyukan Umfraville ba su canza ba, kuma "tsoffin gaskiyar sun kasance: sabis na sarauta, gudanar da gida da kare masarautar". An sanya shi don shiga cikin mamayewar Henry IV na Scotland a cikin 1400, wanda ya zo kaɗan; Umfraville daga baya ya yi nasara a kan babban rundunar sojojin Scotland a Fulhope Law bayan yunkurin kai hari. Ya ci gaba da kare kan iyaka a cikin shekaru goma masu zuwa, kuma kwarewarsa a harkokin siyasa na gida ya taimaka masa ya ba da shawara ga Warden na Gabas ta Gabas, ɗan Sarki, John, Duke na Lancaster. Wataƙila Umfraville ya yi aiki a matsayin'mai kula da' Duke, a cikin tsakiyar tsakiyar da ba ta da yawa a yanzu. A shekara ta 1407, tare da dan dan uwansa Gilbert V de Umfraville, ya halarci, a matsayin babban dan haya, na sabon Bishop na Durham, Thomas Langley.