Direct answer (with an important ambiguity)

The question “How did Spanish clergy influence Pope Leo’s papal administration?” is ambiguous about which Pope Leo is meant—Leo XIII or the current Pope Leo XIV. The Catholic sources provided here contain clear evidence about Leo XIII’s dealings with Spanish clergy, but no direct evidence about Spanish clergy shaping Pope Leo XIV’s administration.

So, from what is actually supported by the supplied texts:

• If you mean Pope Leo XIII: Spanish clergy influence is shown mainly through Holy See support for Spanish clergy formation, especially the Roman College for Spanish clerics. 1
• If you mean Pope Leo XIV: the supplied material does not document an influence by Spanish clergy on his administrative decisions. 2

If “Pope Leo” = Pope Leo XIII: documented influence through clergy formation

Pope Leo XIII explicitly addressed Spanish bishops about the establishment of a Roman college for Spanish clerics, and he framed it as part of a broader pastoral strategy for Spain’s clergy:

• He states that he aimed to “safeguard and augment the Catholic cause” in Spain and to “devote some care to their formation,” with particular attention to young clergy. 1
• He justifies this by appealing to Spain’s historical faith, obedience to the Apostolic See, and the particular importance of training clergy to sustain that fidelity. 1
• In another letter, Leo XIII highlights Spanish devotion to the Apostolic See—including “letters,” “liberality,” and “pilgrimages”—which helps explain why the Holy See would treat Spanish clerical formation as strategically significant. 3

What this means for “papal administration”: even though this is not an organizational chart of governance, it is still an administrative choice: the papacy actively builds institutional capacity (a Rome-based formation center) for a national clerical body, thereby shaping how clergy are formed to serve the Church in fidelity to Rome. 1

If “Pope Leo” = Pope Leo XIV: no direct evidence in the provided sources

For Pope Leo XIV, the supplied sources focus on biography and his roles, not Spanish-clergy patronage or policy influence.

• The biography provided emphasizes his Augustinian formation, studies (including canon law), missionary work in Peru, and later leadership in his Order, plus his service in Roman curial leadership before the papacy. 2
• In the supplied biography excerpts, there is no mention of Spanish clergy influencing his administrative governance (e.g., appointment patterns, curial staffing, directives shaped by Spanish clerical groups). 2

Therefore, based strictly on the provided texts, the correct conclusion is:

• There is not enough sourced information to claim that Spanish clergy influenced Pope Leo XIV’s papal administration in any direct or specific way.

What the Pius XI documents do—and do not—show

You also provided two letters of Pope Pius XI about Spanish clergy circumstances:

• Pius XI expresses concern for the financial hardship of secular and regular clergy in Spain, and he connects this to the Church’s ability to provide for divine worship and pastoral ministry. 4
• He describes the situation as “very sad,” including injustice regarding clergy income. 5

These texts demonstrate the Holy See’s past administrative/pastoral attentiveness to Spanish clergy welfare, but they still do not provide a bridge to Pope Leo XIV’s administration specifically. 4 5

Conclusion

• For Pope Leo XIII: Spanish clergy influence on papal administration is supported by Leo XIII’s direct administrative action—promoting and funding the formation of Spanish clerics in Rome, especially young clergy. 1
• For Pope Leo XIV: the supplied sources do not show any direct influence of Spanish clergy on his papal administrative decisions; the evidence provided relates to his personal formation and curial roles, not Spanish clerical influence. 2