NOTES: See notes on Sir
According to internet information I have, Robert became first Lord of Wormleighton (in Warwickshire) in 1603. The remains of a manor house built at about that time (and half-destroyed in the Civil War) still stand at Wormleighton, so I need to look into whether there is a connection.
The same internet charts list Mary as "Child 7" but also gives her birthdate as 1588, and obviously both of those things can't be true; I assume the children are not listed in birth order.
Son William (2nd Baron) married the daughter of Shakespeare's close friend and patron, Henry Wriothesley, 3rd Earl of Southampton, a leading candidate for the young man addressed in the Sonnets.
The invaluable Spencer Family Web Site provides this biographical account:
"The Spencers have been farmers since pre-Tudor times, coming to prominence in Warwickshire in the fifteenth century. John Spencer became feoffee of Wormleighton in 1469, and a tenant at Althorp in 1486. His nephew another John, through trade in livestock and commodities, then bought both properties outright, was knighted, and so lay the bedrock for the family's fortune. His descendants expanded the holdings through business dealings and marriage into the peerage. However, not until Robert, First Lord Spencer (1570-1627) does a fully-rounded character emerge from history. Thanks in part to the steady accumulation of his forebears he became one of the richest men in the land. He owned almost 20,000 sheep, and with sales of meat, breeding stock and wool, his income was about £8,000 per annum. As a man of standing, he met James I as the royal court travelled down from Scotland in 1603, accompanying it on to London. Meanwhile James' wife was entertained at Althorp, then a secondary residence, with a masque by Ben Jonson. Robert was soon ennobled; and like many Spencers afterwards, almost in spite of himself he suddenly found himself in public service. King James I sent him as ambassador to Wurtemburg to present Duke Frederick with the Order of the Garter. Although 'his skill in antiquities, arms and alliances was singular, Robert appears to have found the expedition more chore than cultural enrichment. Though politically active he soon fades from view."