I came across an interesting concise history of Temple Bar in London from Look Up London on the internet. This covers the origins of the bar, its predecessors, and the Wren archway completed in 1672 and removed in 1878.
The campaign to rescue it from decay at Theobalds Park and for its re-erection on a new site north of St Pauls is one I recall as a substantive piece of conservation and restoration. Indeed I would have wished to go further and re-erect it on its original site - the Temple Bar Memorial from 1880 could have been re-located and preserved, though it is by no means a great piece of mid-Victoriana. That I, just about, concede might as a plan have been too ambitious. Nonetheless the scheme which restored Temple Bar to the City was an excellent one, and does allow people to stand back and appreciate the architecture, which its on The Strand might not permit today.
The illustrated account can be seen at The History of Temple Bar
The article refers to the head of Col. Francis Towneley that was displayed above the Bar after his execution in 1746. I posted about the subsequent history of his head in The problem with Uncle Frank