Belgrave St Peter's marched into the 20th Century as
Belgrave Rugby Football Club and before the first world war another Belgrave Rovers team was to come and go.
In the 1900/01 season H. Berrington was elected 1st team captain and L. Bradbury vice-captain, S.A. Anstee 2nd team captain and F. Chapman vice-captain. Sidney Alexander Anstee became club secretary in 1902, a position he was to hold for 50 years. During that time Sid Anstee served on the committee of the Leicestershire Rugby Union. He was also president of Leicestershire in 1926/27. Sid Anstee's son. Herbert better known as "Knibbs" was still and active member of the club up until 198888, serving as vice-president and groundsman marking the pitch out on match days as he had done for the last 30 years.
Belgrave first won the Midland Counties Cup in 1898 and then went on to win it every year up to 1905, eight consecutive times. It was during Leicester's tremendous cup run that Belgrave met them on two occasions. In 1899 Belgrave were really given a lesson in Rugby football losing in the second round game by 68 points to 3. A second meeting, with Leicester in 1903, again in the second round, was to prove costly, losing this time 54 points to nil. Although being well beaten by Leicester, 1903 was by no means a poor season; it was a highly successful one, because that year Belgrave won the Senior Cup, Rolleston Cup and the Leicester Alliance Combination, the first time any club had won all three competitions in the same season.
The club never settled on a permanent ground until 1911 when they managed to obtain the use of Belgrave Pastures where they are to this day. Until then the club seemed to move around from season to season. In 1901 they played on a ground owned by Mr Grewcock and in 1903 rented Mr Gask's field for two shillings and sixpence (12 ½ p) a match. Five pounds a season was the rent paid for Mr Felstead's field in 1904 and that went up to six pounds in 1905. The club returned to Mr Gask's field in 1906 and it would appear that, in an effort to cut rent costs, they started sharing the ground with other clubs, sharing first with Invicta FC and later with Anchor. In 1907 the club played on Mr Geary's field at a rent of six pounds ten shillings. This was almost increased to seven pounds in1910, but after consultation Mr Geary agreed to leave the rent as it was. When the use of Belgrave Pastures was obtained in 1911 it would appear that the rent was a lot more reasonable; the 1913 minutes state "the rent of the pastures will this season be £3 instead of £2".
Although not having a permanent ground until just before the 1914/18 war, their playing record during that period was quite good. They reached the third round of the Midlands County Cup on four occasions. First was in 1908 when they narrowly lost to Oadby by 13 points to 11. The third round game against Rugby in 1910 has already been mentioned and the other third round appearances were in 1913 when Stratford-On-Avon won 27 points to nil and 1914 when Aston Old Edwardians won by 25 points to nil.
Belgrave won the Leicester Alliance Combination two years running in 1902 and 1903 and the senior cup in 1903, 1906 and 1907. They won the Rolleston Cup no fewer than six times in a ten year period holding it in 1901, 1903, 1904, 1905, 1906 and 1910.
Of all the games played by Belgrave up to the Great War I would like to mention one they lost. It was the policy of the Leicestershire Rugby Union to arrange exhibition and important competition games to be played in the County where no Rugby existed.
This particular game was the Leicester Alliance Combination game against Granville and was played on 27th February 1904 at Anstey. Belgrave, who were the Alliance Combination winners the two previous seasons, were level with Granville on 20 points and travelled to Anstey with a good number of supporters and a lot of confidence. Granville took them by storm by winning the game 14 points to nil and the Alliance Combination with 22 points to Belgrave's 20. A Belgrave supporter at the game wrote a poem entitled "In memory of Dummy Town". Dummy Town is the old nickname for the Belgrave area possibly because of the number of Cul-de-sacs or "Dummies"

With the advent of the Great War in 1914 club activities ceased until 29th August 1919 when a general meeting was held and the club officials for the following season elected. Walter Buckler was elected captain and Mr Arthur Voce vice-captain. Walter Buckler and his brother William were both capped by the County.
The club's first game that season was a friendly played on the 20th September 1919 against Medway Athletic, which they won 8 points to 3. The following week they lost to South Wigston by a try to nil. The club were on the winning trail in 1920 winning the Senior and Rolleston Cup and finished the season as Alliance Combination Champions. They won the Senior cup in 1924 and again in 1925 when once again they finished the season as Alliance Combination Champions.
The 1926 season saw them as Alliance Combination winners, Senior Cup winners and Rolleston Cup finalists, losing to Lutterworth by 5 points to 3. The following year the club were again Alliance Combination winners; They also won both the Senior and Rolleston Cup, winning the Senior Cup in convincing style scoring six tries to nil against Leicester Police. They did not have things all their own way in the Rolleston Cup final when they played South Wigston on a rain swept Leicester ground. After extra time the score was still a try each and a replay was played on Stoneygate's ground, which at that time was on the Aylestone Road. This time Belgrave won 3 tries to nil.
1927 was the club's best ever season. By winning the County's three major competitions they equalled their own record breaking season of 1903 and even improved on this by finishing the season with no less than five cups in all. This is believed to be a record in local Rugby to this day.