Gilbert was born in Sempringham, Lincolnshire. England, in 1083. From the day he was born, Gilbert suffered from a deformed spine and in later life this prevented him from following the family of bearing arms and becoming a knight.
Rather than live a helpless life, Gilbert made full use of his other abilities by becoming a scholar, teacher, and then at the age of 40, a priest.
Breaking from the tradition of relatively luxurious monasteries of the time, Gilbert followed St. Benedict's example and established a simple monastery that recognised poverty as a virtue.
Gilbert laboured for the rest of his long life (reportedly to have lived 106 years) looking after the poor and needy. He could not stand erect but this did not prevent him from doing the Lord's work.
Portate is from the Latin portare 'to carry'. From this word we get words like 'portable' and 'porter'. There are many other diagonal crosses; for example in the logo of the Christian Methodist Episcopal Church (CME) and the more generic St. Andrew's Cross, as seen in the logo of the Christian Church (Disciples of Christ) (CCDC).
A cross is usually shown erect, as it would be when used for crucifixion. The Portate Cross differs in that it is borne diagonally, as it would be when the victim bears the cross-bar over his shoulder as he drags it along the ground to the crucifixion site.
The Portate Cross reminds us of the cross carried by Jesus prior to his Crucifixion and that any cross we bear in his name will be nothing compared to his suffering. (See also Angus Dei).